TY  - GEN
A1  - Wolff, Christian Michael
A1  - Canil, Laura
A1  - Rehermann, Carolin
A1  - Nguyen, Ngoc Linh
A1  - Zu, Fengshuo
A1  - Ralaiarisoa, Maryline
A1  - Caprioglio, Pietro
A1  - Fiedler, Lukas
A1  - Stolterfoht, Martin
A1  - Kogikoski, Junior, Sergio
A1  - Bald, Ilko
A1  - Koch, Norbert
A1  - Unger, Eva L.
A1  - Dittrich, Thomas
A1  - Abate, Antonio
A1  - Neher, Dieter
T1  - Correction to 'Perfluorinated self-assembled monolayers enhance the stability and efficiency of inverted perovskite solar cells' (2020, 14 (2), 1445−1456)
T2  - ACS nano
Y1  - 2020
U6  - https://doi.org/10.1021/acsnano.0c08081
SN  - 1936-0851
SN  - 1936-086X
VL  - 14
IS  - 11
SP  - 16156
EP  - 16156
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Vinke, Kira
A1  - Gabrysch, Sabine
A1  - Paoletti, Emanuela
A1  - Rockström, Johan
A1  - Schellnhuber, Hans Joachim
T1  - Corona and the climate
BT  - a comparison of two emergencies
JF  - Global sustainability
N2  - Lessons from the corona crisis can help manage the even more daunting challenge of anthropogenic global warming.
KW  - adaptation and mitigation
KW  - ecology and biodiversity
KW  - human behaviour
KW  - natural resources (biological and non-biological)
KW  - policies
KW  - politics
KW  - and governance
Y1  - 2020
U6  - https://doi.org/10.1017/sus.2020.20
SN  - 2059-4798
VL  - 3
PB  - Cambridge Univ. Press
CY  - Cambridge
ER  - 
TY  - THES
A1  - Mandal, Partha Sarathi
T1  - Controlling the surface band gap in topological states of matter
N2  - In the present study, we employ the angle-resolved photoemission spectroscopy (ARPES) technique to study the electronic structure of topological states of matter. In particular, the so-called topological crystalline insulators (TCIs) Pb1-xSnxSe and Pb1-xSnxTe, and the Mn-doped Z2 topological insulators (TIs) Bi2Te3 and Bi2Se3. The Z2 class of strong topological insulators is protected by time-reversal symmetry and is characterized by an odd number of metallic Dirac type surface states in the surface Brillouin zone. The topological crystalline insulators on the other hand are protected by the individual crystal symmetries and exhibit an even number of Dirac cones. 

The topological properties of the lead tin chalcogenides topological crystalline insulators can be tuned by temperature and composition. Here, we demonstrate that Bi-doping of the Pb1-xSnxSe(111) epilayers induces a quantum phase transition from a topological crystalline insulator to a Z2 topological insulator. This occurs because Bi-doping lifts the fourfold valley degeneracy in the bulk. As a consequence a gap appears at ⌈¯, while the three Dirac cones at the M̅ points of the surface Brillouin zone remain intact. We interpret this new phase transition is caused by lattice distortion. Our findings extend the topological phase diagram enormously and make strong topological insulators switchable by distortions or electric field. In contrast, the bulk Bi doping of epitaxial Pb1-xSnxTe(111) films induces a giant Rashba splitting at the surface that can be tuned by the doping level. Tight binding calculations identify their origin as Fermi level pinning by trap states at the surface.

Magnetically doped topological insulators enable the quantum anomalous Hall effect (QAHE) which provide quantized edge states for lossless charge transport applications. The edge states are hosted by a magnetic energy gap at the Dirac point which has not been experimentally observed to date. Our low temperature ARPES studies unambiguously reveal the magnetic gap of Mn-doped Bi2Te3. Our analysis shows a five times larger gap size below the Tc than theoretically predicted. We assign this enhancement to a remarkable structure modification induced by Mn doping. Instead of a disordered impurity system, a self-organized alternating sequence of MnBi2Te4 septuple and Bi2Te3quintuple layers is formed. This enhances the wave-function overlap and gives rise to a large magnetic gap. Mn-doped Bi2Se3 forms similar heterostructure, but only a nonmagnetic gap is observed in this system. This correlates with the difference in magnetic anisotropy due to the much larger spin-orbit interaction in Bi2Te3 compared to Bi2Se3. These findings provide crucial insights for pushing lossless transport in topological insulators towards room-temperature applications.
N2  - In der vorliegenden Studie verwenden wir die Methode der winkelaufgelösten Photoemissionsspektroskopie (ARPES) zur Untersuchung der elektronischen Struktur von topologischen Zuständen der Materie. 
Insbesondere die sogenannten topologischen kristallinen Isolatoren (TCI) Pb1-xSnxSe und Pb1-xSnxTe sowie die Mn-dotierten Z2 topologischen Isolatoren (TI)  Bi2Te3 und Bi2Se3. Die Z2-Klasse der starken topologischen Isolatoren ist durch Zeitumkehrsymmetrie geschützt und durch eine ungerade Anzahl metallischer Dirac-Oberflächenzustände in der Oberflächenbrillouinzone gekennzeichnet. 
Die topologischen kristallinen Isolatoren hingegen sind durch einzelne Kristallsymmetrien geschützt und weisen eine gerade Anzahl von Dirac-Kegeln auf. Die topologischen Eigenschaften von Blei-Zinn-Chalkogenid-TCI lassen sich durch Temperatur sowie chemische Zusammensetzung einstellen. Hier wird gezeigt, dass Bi-Dotierung von eptiaktischen Pb1-xSnxSe(111)-Schichten einen Quantenphasenübergang von einem topologischen kristallinen Isolator zu einem Z2-topologischen Isolator hervorruft. Dies geschieht, weil die Dotierung mit Bi die vierfache Valley-Entartung im Volumen aufhebt. 
Als Konsequenz entsteht eine Lücke bei ⌈¯, während die drei Dirac-Kegel an den M̅-Punkten der Oberflächenbrillouinzone intakt bleiben. Wir interpretieren diesen neuen Phasenübergang als durch eine Gitterverzerrung verursacht. Unsere Ergebnisse erweitern das topologische Phasendiagramm enorm und machen starke topologische Isolatoren durch Verzerrungen oder elektrische Felder schaltbar. Im Gegensatz dazu induziert eine Bi-Dotierung im Volumen von epitaktischen Pb1-xSnxTe(111)-Schichten eine riesige Rashba-Aufspaltung an der Oberfläche, die durch das Ausmaß der Dotierung eingestellt werden kann. Tight-Binding-Berechnungen identifizieren ihren Ursprung in einem Fermi-Niveau-Pinning durch Trap-Zustände an der Oberfläche.
Magnetisch dotierte topologische Isolatoren ermöglichen den quantisierten anomalen Hall-Effekt (QAHE), der quantisierte Kantenzustände liefert, die für verlustfreien Ladungstransport eingesetzt werden können. Die Kantenzustände treten in einer magnetischen Energielücke am Dirac-Punkt auf, die bisher noch nicht experimentell beobachtet wurde. 
Unsere Tieftemperatur-ARPES-Untersuchungen weisen die magnetische Energielücke in Mn dotiertem Bi2Te3 eindeutig nach. Unsere Analyse zeigt unterhalb von Tc eine viermal größere Energielücke als theoretisch vorhergesagt. Wir führen diese Erhöhung auf eine bemerkenswerte Strukturmodifikation durch die Mn-Dotierung zurück. Statt eines Systems mit ungeordneten Mn Verunreinigungen entsteht eine selbstorganisierte alternierende Sequenz von MnBi2Te4-Septupel- und Bi2Te3-Quintupel-Schichten. 
Das erhöht den Überlapp der Wellenfunktionen und führt zu der großen magnetischen Energielücke. Mn-dotiertes Bi2Se3 bildet ähnliche Heterostrukturen aus, jedoch wird in diesem System nur eine nichtmagnetische Energielücke beobachtet. Dies korreliert mit der unterschiedlichen magnetischen Anisotropie aufgrund der viel größeren Spin-Bahn-Wechselwirkung im Bi2Te3 im Vergleich zu Bi2Se3. Diese Resultate liefern entscheidende Erkenntnisse, um verlustfreien Transport in topologischen Isolatoren für Anwendungen bei Raumtemperatur weiterzuentwickeln.
KW  - ARPES
KW  - Topological Insulator
KW  - Topological Crystalline Insulator
KW  - Rashba effect
KW  - Rashba-Effekt
KW  - Topologischer kristalliner Isolator
KW  - Topologischer Isolator
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-480459
ER  - 
TY  - JOUR
A1  - Rosenblum, Michael
T1  - Controlling collective synchrony in oscillatory ensembles by precisely timed pulses
JF  - Chaos : an interdisciplinary journal of nonlinear science
N2  - We present an efficient technique for control of synchrony in a globally coupled ensemble by pulsatile action. We assume that we can observe the collective oscillation and can stimulate all elements of the ensemble simultaneously. We pay special attention to the minimization of intervention into the system. The key idea is to stimulate only at the most sensitive phase. To find this phase, we implement an adaptive feedback control. Estimating the instantaneous phase of the collective mode on the fly, we achieve efficient suppression using a few pulses per oscillatory cycle. We discuss the possible relevance of the results for neuroscience, namely, for the development of advanced algorithms for deep brain stimulation, a medical technique used to treat Parkinson's disease.
Y1  - 2020
U6  - https://doi.org/10.1063/5.0019823
SN  - 1054-1500
SN  - 1089-7682
VL  - 30
IS  - 9
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - GEN
A1  - Granado, Felipe Le Vot
A1  - Abad, Enrique
A1  - Metzler, Ralf
A1  - Yuste, Santos B.
T1  - Continuous time random walk in a velocity field
BT  - role of domain growth, Galilei-invariant advection-diffusion, and kinetics of particle mixing
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - We consider the emerging dynamics of a separable continuous time random walk (CTRW) in the case when the random walker is biased by a velocity field in a uniformly growing domain. Concrete examples for such domains include growing biological cells or lipid vesicles, biofilms and tissues, but also macroscopic systems such as expanding aquifers during rainy periods, or the expanding Universe. The CTRW in this study can be subdiffusive, normal diffusive or superdiffusive, including the particular case of a Lévy flight. We first consider the case when the velocity field is absent. In the subdiffusive case, we reveal an interesting time dependence of the kurtosis of the particle probability density function. In particular, for a suitable parameter choice, we find that the propagator, which is fat tailed at short times, may cross over to a Gaussian-like propagator. We subsequently incorporate the effect of the velocity field and derive a bi-fractional diffusion-advection equation encoding the time evolution of the particle distribution. We apply this equation to study the mixing kinetics of two diffusing pulses, whose peaks move towards each other under the action of velocity fields acting in opposite directions. This deterministic motion of the peaks, together with the diffusive spreading of each pulse, tends to increase particle mixing, thereby counteracting the peak separation induced by the domain growth. As a result of this competition, different regimes of mixing arise. In the case of Lévy flights, apart from the non-mixing regime, one has two different mixing regimes in the long-time limit, depending on the exact parameter choice: in one of these regimes, mixing is mainly driven by diffusive spreading, while in the other mixing is controlled by the velocity fields acting on each pulse. Possible implications for encounter–controlled reactions in real systems are discussed.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1005 
KW  - diffusion
KW  - expanding medium
KW  - continuous time random walk
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-479997
SN  - 1866-8372
IS  - 1005
SP  - 28
ER  - 
TY  - JOUR
A1  - Granado, Felipe Le Vot
A1  - Abad, Enrique
A1  - Metzler, Ralf
A1  - Yuste, Santos B.
T1  - Continuous time random walk in a velocity field
BT  - role of domain growth, Galilei-invariant advection-diffusion, and kinetics of particle mixing
JF  - New Journal of Physics
N2  - We consider the emerging dynamics of a separable continuous time random walk (CTRW) in the case when the random walker is biased by a velocity field in a uniformly growing domain. Concrete examples for such domains include growing biological cells or lipid vesicles, biofilms and tissues, but also macroscopic systems such as expanding aquifers during rainy periods, or the expanding Universe. The CTRW in this study can be subdiffusive, normal diffusive or superdiffusive, including the particular case of a Lévy flight. We first consider the case when the velocity field is absent. In the subdiffusive case, we reveal an interesting time dependence of the kurtosis of the particle probability density function. In particular, for a suitable parameter choice, we find that the propagator, which is fat tailed at short times, may cross over to a Gaussian-like propagator. We subsequently incorporate the effect of the velocity field and derive a bi-fractional diffusion-advection equation encoding the time evolution of the particle distribution. We apply this equation to study the mixing kinetics of two diffusing pulses, whose peaks move towards each other under the action of velocity fields acting in opposite directions. This deterministic motion of the peaks, together with the diffusive spreading of each pulse, tends to increase particle mixing, thereby counteracting the peak separation induced by the domain growth. As a result of this competition, different regimes of mixing arise. In the case of Lévy flights, apart from the non-mixing regime, one has two different mixing regimes in the long-time limit, depending on the exact parameter choice: in one of these regimes, mixing is mainly driven by diffusive spreading, while in the other mixing is controlled by the velocity fields acting on each pulse. Possible implications for encounter–controlled reactions in real systems are discussed.
KW  - diffusion
KW  - expanding medium
KW  - continuous time random walk
Y1  - 2020
U6  - https://doi.org/10.1088/1367-2630/ab9ae2
SN  - 1367-2630
VL  - 22
PB  - Dt. Physikalische Ges.
CY  - Bad Honnef
ER  - 
TY  - JOUR
A1  - Samajdar, Anuradha
A1  - Dietrich, Tim
T1  - Constructing Love-Q relations with gravitational wave detections
JF  - Physical review : D, Particles, fields, gravitation, and cosmology
N2  - Quasiuniversal relations between the tidal deformability and the quadrupole moment of neutron stars are predicted by theoretical computations, but have not been measured experimentally. We simulate 120 binary neutron star sources and find that Advanced LIGO and Advanced Virgo at design sensitivity could find possible deviations from predicted relations if the neutron stars are highly spinning. A network of envisaged third generation detectors will even allow extracting such relations, providing new tests of general relativity and nuclear physics predictions.
Y1  - 2020
U6  - https://doi.org/10.1103/PhysRevD.101.124014
SN  - 1550-7998
SN  - 1550-2368
VL  - 101
IS  - 12
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Kurilovich, Aleksandr A.
A1  - Mantsevich, Vladimir
A1  - Stevenson, Keith J.
A1  - Chechkin, Aleksei V.
A1  - Palyulin, V. V.
T1  - Complex diffusion-based kinetics of photoluminescence in semiconductor nanoplatelets
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - We present a diffusion-based simulation and theoretical models for explanation of the photoluminescence (PL) emission intensity in semiconductor nanoplatelets. It is shown that the shape of the PL intensity curves can be reproduced by the interplay of recombination, diffusion and trapping of excitons. The emission intensity at short times is purely exponential and is defined by recombination. At long times, it is governed by the release of excitons from surface traps and is characterized by a power-law tail. We show that the crossover from one limit to another is controlled by diffusion properties. This intermediate region exhibits a rich behaviour depending on the value of diffusivity. The proposed approach reproduces all the features of experimental curves measured for different nanoplatelet systems.
Y1  - 2020
U6  - https://doi.org/10.1039/d0cp03744c
SN  - 1463-9076
SN  - 1463-9084
VL  - 22
IS  - 42
SP  - 24686
EP  - 24696
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Marschall, Raphael
A1  - Skorov, Yuri
A1  - Zakharov, Vladimir
A1  - Rezac, Ladislav
A1  - Gerig, Selina-Barbara
A1  - Christou, Chariton
A1  - Dadzie, S. Kokou
A1  - Migliorini, Alessandra
A1  - Rinaldi, Giovanna
A1  - Agarwal, Jessica
A1  - Vincent, Jean-Baptiste
A1  - Kappel, David
T1  - Cometary comae-surface links the physics of gas and dust from the surface to a spacecraft
JF  - Space science reviews
N2  - A comet is a highly dynamic object, undergoing a permanent state of change. These changes have to be carefully classified and considered according to their intrinsic temporal and spatial scales. The Rosetta mission has, through its contiguous in-situ and remote sensing coverage of comet 67P/Churyumov-Gerasimenko (hereafter 67P) over the time span of August 2014 to September 2016, monitored the emergence, culmination, and winding down of the gas and dust comae. This provided an unprecedented data set and has spurred a large effort to connect in-situ and remote sensing measurements to the surface. In this review, we address our current understanding of cometary activity and the challenges involved when linking comae data to the surface. We give the current state of research by describing what we know about the physical processes involved from the surface to a few tens of kilometres above it with respect to the gas and dust emission from cometary nuclei. Further, we describe how complex multidimensional cometary gas and dust models have developed from the Halley encounter of 1986 to today. This includes the study of inhomogeneous outgassing and determination of the gas and dust production rates. Additionally, the different approaches used and results obtained to link coma data to the surface will be discussed. We discuss forward and inversion models and we describe the limitations of the respective approaches. The current literature suggests that there does not seem to be a single uniform process behind cometary activity. Rather, activity seems to be the consequence of a variety of erosion processes, including the sublimation of both water ice and more volatile material, but possibly also more exotic processes such as fracture and cliff erosion under thermal and mechanical stress, sub-surface heat storage, and a complex interplay of these processes. Seasons and the nucleus shape are key factors for the distribution and temporal evolution of activity and imply that the heliocentric evolution of activity can be highly individual for every comet, and generalisations can be misleading.
KW  - comets
KW  - coma
KW  - gas
KW  - dust
KW  - dynamics
KW  - modelling
KW  - inversion
Y1  - 2020
U6  - https://doi.org/10.1007/s11214-020-00744-0
SN  - 0038-6308
SN  - 1572-9672
VL  - 216
IS  - 8
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - GEN
A1  - Alirezaeizanjani, Zahra
A1  - Großmann, Robert
A1  - Pfeifer, Veronika
A1  - Hintsche, Marius
A1  - Beta, Carsten
T1  - Chemotaxis strategies of bacteria with multiple run modes
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Bacterial chemotaxis-a fundamental example of directional navigation in the living world-is key to many biological processes, including the spreading of bacterial infections. Many bacterial species were recently reported to exhibit several distinct swimming modes-the flagella may, for example, push the cell body or wrap around it. How do the different run modes shape the chemotaxis strategy of a multimode swimmer? Here, we investigate chemotactic motion of the soil bacterium Pseudomonas putida as a model organism. By simultaneously tracking the position of the cell body and the configuration of its flagella, we demonstrate that individual run modes show different chemotactic responses in nutrition gradients and, thus, constitute distinct behavioral states. On the basis of an active particle model, we demonstrate that switching between multiple run states that differ in their speed and responsiveness provides the basis for robust and efficient chemotaxis in complex natural habitats.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1418 
KW  - instability
KW  - flagellum
KW  - exploit
KW  - time
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-519098
SN  - 1866-8372
IS  - 22
ER  - 
TY  - JOUR
A1  - Alirezaeizanjani, Zahra
A1  - Großmann, Robert
A1  - Pfeifer, Veronika
A1  - Hintsche, Marius
A1  - Beta, Carsten
T1  - Chemotaxis strategies of bacteria with multiple run modes
JF  - Science advances
N2  - Bacterial chemotaxis-a fundamental example of directional navigation in the living world-is key to many biological processes, including the spreading of bacterial infections. Many bacterial species were recently reported to exhibit several distinct swimming modes-the flagella may, for example, push the cell body or wrap around it. How do the different run modes shape the chemotaxis strategy of a multimode swimmer? Here, we investigate chemotactic motion of the soil bacterium Pseudomonas putida as a model organism. By simultaneously tracking the position of the cell body and the configuration of its flagella, we demonstrate that individual run modes show different chemotactic responses in nutrition gradients and, thus, constitute distinct behavioral states. On the basis of an active particle model, we demonstrate that switching between multiple run states that differ in their speed and responsiveness provides the basis for robust and efficient chemotaxis in complex natural habitats.
KW  - exploit
KW  - flagellum
KW  - instability
KW  - time
Y1  - 2020
U6  - https://doi.org/10.1126/sciadv.aaz6153
SN  - 2375-2548
VL  - 6
IS  - 22
PB  - American Association for the Advancement of Science
CY  - Washington
ER  - 
TY  - JOUR
A1  - Erler, Alexander
A1  - Riebe, Daniel
A1  - Beitz, Toralf
A1  - Löhmannsröben, Hans-Gerd
A1  - Grothusheitkamp, Daniela
A1  - Kunz, Thomas
A1  - Methner, Frank-Jürgen
T1  - Characterization of volatile metabolites formed by molds on barley by mass and ion mobility spectrometry
JF  - Journal of mass spectrometr
N2  - The contamination of barley by molds on the field or in storage leads to the spoilage of grain and the production of mycotoxins, which causes major economic losses in malting facilities and breweries. Therefore, on-site detection of hidden fungus contaminations in grain storages based on the detection of volatile marker compounds is of high interest. In this work, the volatile metabolites of 10 different fungus species are identified by gas chromatography (GC) combined with two complementary mass spectrometric methods, namely, electron impact (EI) and chemical ionization at atmospheric pressure (APCI)-mass spectrometry (MS). The APCI source utilizes soft X-radiation, which enables the selective protonation of the volatile metabolites largely without side reactions. Nearly 80 volatile or semivolatile compounds from different substance classes, namely, alcohols, aldehydes, ketones, carboxylic acids, esters, substituted aromatic compounds, alkenes, terpenes, oxidized terpenes, sesquiterpenes, and oxidized sesquiterpenes, could be identified. The profiles of volatile and semivolatile metabolites of the different fungus species are characteristic of them and allow their safe differentiation. The application of the same GC parameters and APCI source allows a simple method transfer from MS to ion mobility spectrometry (IMS), which permits on-site analyses of grain stores. Characterization of IMS yields limits of detection very similar to those of APCI-MS. Accordingly, more than 90% of the volatile metabolites found by APCI-MS were also detected in IMS. In addition to different fungus genera, different species of one fungus genus could also be differentiated by GC-IMS.
KW  - APCI
KW  - fungus
KW  - gas chromatography
KW  - ion mobility spectrometry
KW  - mass
KW  - spectrometry
KW  - mold
KW  - soft X-ray
Y1  - 2020
U6  - https://doi.org/10.1002/jms.4501
SN  - 1076-5174
SN  - 1096-9888
VL  - 55
IS  - 5
SP  - 1
EP  - 10
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Schulz, Christian
A1  - Lieutenant, Klaus
A1  - Xiao, Jie
A1  - Hofmann, Tommy
A1  - Wong, Deniz
A1  - Habicht, Klaus
T1  - Characterization of the soft X-ray spectrometer PEAXIS at BESSY II
JF  - Journal of synchrotron radiation
N2  - The performance of the recently commissioned spectrometer PEAXIS for resonant inelastic soft X-ray scattering (RIXS) and X-ray photoelectron spectroscopy and its hosting beamline U41-PEAXIS at the BESSY II synchrotron are characterized. The beamline provides linearly polarized light from 180 eV to 1600 eV allowing for RIXS measurements in the range 200-1200 eV. The monochromator optics can be operated in different configurations to provide either high flux with up to 10(12) photons s(-1) within the focal spot at the sample or high energy resolution with a full width at half maximum of <40 meV at an incident photon energy of similar to 400 eV. The measured total energy resolution of the RIXS spectrometer is in very good agreement with theoretically predicted values obtained by ray-tracing simulations. PEAXIS features a 5 m-long RIXS spectrometer arm that can be continuously rotated about the sample position by 106 degrees within the horizontal photon scattering plane, thus enabling the study of momentum-transfer-dependent excitations. Selected scientific examples are presented to demonstrate the instrument capabilities, including measurements of excitations in single-crystalline NiO and in liquid acetone employing a fluid cell sample manipulator. Planned upgrades of the beamline and the RIXS spectrometer to further increase the energy resolution to similar to 100 meV at 1000 eV incident photon energy are discussed.
KW  - resonant inelastic X-ray scattering
KW  - X-ray photoelectron spectroscopy
KW  - soft X-ray spectroscopy
KW  - soft X-ray beamline
KW  - X-ray emission
KW  - X-ray
KW  - absorption
KW  - BESSY II
Y1  - 2020
U6  - https://doi.org/10.1107/S1600577519014887
SN  - 1600-5775
VL  - 27
SP  - 238
EP  - 249
PB  - International Union of Crystallography
CY  - Chester
ER  - 
TY  - GEN
A1  - Schulz, Christian
A1  - Lieutenant, Klaus
A1  - Xiao, Jie
A1  - Hofmann, Tommy
A1  - Wong, Deniz
A1  - Habicht, Klaus
T1  - Characterization of the soft X-ray spectrometer PEAXIS at BESSY II
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The performance of the recently commissioned spectrometer PEAXIS for resonant inelastic soft X-ray scattering (RIXS) and X-ray photoelectron spectroscopy and its hosting beamline U41-PEAXIS at the BESSY II synchrotron are characterized. The beamline provides linearly polarized light from 180 eV to 1600 eV allowing for RIXS measurements in the range 200-1200 eV. The monochromator optics can be operated in different configurations to provide either high flux with up to 10(12) photons s(-1) within the focal spot at the sample or high energy resolution with a full width at half maximum of <40 meV at an incident photon energy of similar to 400 eV. The measured total energy resolution of the RIXS spectrometer is in very good agreement with theoretically predicted values obtained by ray-tracing simulations. PEAXIS features a 5 m-long RIXS spectrometer arm that can be continuously rotated about the sample position by 106 degrees within the horizontal photon scattering plane, thus enabling the study of momentum-transfer-dependent excitations. Selected scientific examples are presented to demonstrate the instrument capabilities, including measurements of excitations in single-crystalline NiO and in liquid acetone employing a fluid cell sample manipulator. Planned upgrades of the beamline and the RIXS spectrometer to further increase the energy resolution to similar to 100 meV at 1000 eV incident photon energy are discussed.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1355 
KW  - resonant inelastic X-ray scattering;
KW  - X-ray photoelectron spectroscopy
KW  - soft X-ray spectroscopy
KW  - soft X-ray beamline
KW  - X-ray emission
KW  - X-ray absorption
KW  - BESSY II.
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-549928
SN  - 1866-8372
ER  - 
TY  - JOUR
A1  - Emanuel, Marc D.
A1  - Cherstvy, Andrey G.
A1  - Metzler, Ralf
A1  - Gompper, Gerhard
T1  - Buckling transitions and soft-phase invasion of two-component icosahedral shells
JF  - Physical review / publ. by The American Physical Society. E, Statistical, nonlinear, and soft matter physics
N2  - What is the optimal distribution of two types of crystalline phases on the surface of icosahedral shells, such as of many viral capsids? We here investigate the distribution of a thin layer of soft material on a crystalline convex icosahedral shell. We demonstrate how the shapes of spherical viruses can be understood from the perspective of elasticity theory of thin two-component shells. We develop a theory of shape transformations of an icosahedral shell upon addition of a softer, but still crystalline, material onto its surface. We show how the soft component "invades" the regions with the highest elastic energy and stress imposed by the 12 topological defects on the surface. We explore the phase diagram as a function of the surface fraction of the soft material, the shell size, and the incommensurability of the elastic moduli of the rigid and soft phases. We find that, as expected, progressive filling of the rigid shell by the soft phase starts from the most deformed regions of the icosahedron. With a progressively increasing soft-phase coverage, the spherical segments of domes are filled first (12 vertices of the shell), then the cylindrical segments connecting the domes (30 edges) are invaded, and, ultimately, the 20 flat faces of the icosahedral shell tend to be occupied by the soft material. We present a detailed theoretical investigation of the first two stages of this invasion process and develop a model of morphological changes of the cone structure that permits noncircular cross sections. In conclusion, we discuss the biological relevance of some structures predicted from our calculations, in particular for the shape of viral capsids.
Y1  - 2020
U6  - https://doi.org/10.1103/PhysRevE.102.062104
SN  - 2470-0045
SN  - 2470-0053
SN  - 2470-0061
SN  - 1538-4519
VL  - 102
IS  - 6
PB  - Woodbury
CY  - New York
ER  - 
TY  - JOUR
A1  - Perdigón-Toro, Lorena
A1  - Zhang, Huotian
A1  - Markina, Anastaa si
A1  - Yuan, Jun
A1  - Hosseini, Seyed Mehrdad
A1  - Wolff, Christian Michael
A1  - Zuo, Guangzheng
A1  - Stolterfoht, Martin
A1  - Zou, Yingping
A1  - Gao, Feng
A1  - Andrienko, Denis
A1  - Shoaee, Safa
A1  - Neher, Dieter
T1  - Barrierless free charge generation in the high-performance PM6:Y6 bulk heterojunction non-fullerene solar cell
JF  - Advanced materials
N2  - Organic solar cells are currently experiencing a second golden age thanks to the development of novel non-fullerene acceptors (NFAs). Surprisingly, some of these blends exhibit high efficiencies despite a low energy offset at the heterojunction. Herein, free charge generation in the high-performance blend of the donor polymer PM6 with the NFA Y6 is thoroughly investigated as a function of internal field, temperature and excitation energy. Results show that photocurrent generation is essentially barrierless with near-unity efficiency, regardless of excitation energy. Efficient charge separation is maintained over a wide temperature range, down to 100 K, despite the small driving force for charge generation. Studies on a blend with a low concentration of the NFA, measurements of the energetic disorder, and theoretical modeling suggest that CT state dissociation is assisted by the electrostatic interfacial field which for Y6 is large enough to compensate the Coulomb dissociation barrier.
KW  - driving force
KW  - non-fullerene acceptors
KW  - organic solar cells
KW  - photocurrent generation
Y1  - 2020
U6  - https://doi.org/10.1002/adma.201906763
SN  - 0935-9648
SN  - 1521-4095
VL  - 32
IS  - 9
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Munyaev, Vyacheslav
A1  - Smirnov, Lev A.
A1  - Kostin, Vasily
A1  - Osipov, Grigory V.
A1  - Pikovskij, Arkadij
T1  - Analytical approach to synchronous states of globally coupled noisy rotators
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - We study populations of globally coupled noisy rotators (oscillators with inertia) allowing a nonequilibrium transition from a desynchronized state to a synchronous one (with the nonvanishing order parameter). The newly developed analytical approaches resulted in solutions describing the synchronous state with constant order parameter for weakly inertial rotators, including the case of zero inertia, when the model is reduced to the Kuramoto model of coupled noise oscillators. These approaches provide also analytical criteria distinguishing supercritical and subcritical transitions to the desynchronized state and indicate the universality of such transitions in rotator ensembles. All the obtained analytical results are confirmed by the numerical ones, both by direct simulations of the large ensembles and by solution of the associated Fokker-Planck equation. We also propose generalizations of the developed approaches for setups where different rotators parameters (natural frequencies, masses, noise intensities, strengths and phase shifts in coupling) are dispersed.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1188 
KW  - coupled rotators
KW  - synchronization transition
KW  - hysteresis
KW  - Kuramoto model
KW  - noisy systems
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-524261
SN  - 1866-8372
IS  - 2
ER  - 
TY  - JOUR
A1  - Munyaev, Vyacheslav O.
A1  - Smirnov, Lev A.
A1  - Kostin, Vasily A.
A1  - Osipov, Grigory V.
A1  - Pikovskij, Arkadij
T1  - Analytical approach to synchronous states of globally coupled noisy rotators
JF  - New journal of physics : the open-access journal for physics
N2  - We study populations of globally coupled noisy rotators (oscillators with inertia) allowing a nonequilibrium transition from a desynchronized state to a synchronous one (with the nonvanishing order parameter). The newly developed analytical approaches resulted in solutions describing the synchronous state with constant order parameter for weakly inertial rotators, including the case of zero inertia, when the model is reduced to the Kuramoto model of coupled noise oscillators. These approaches provide also analytical criteria distinguishing supercritical and subcritical transitions to the desynchronized state and indicate the universality of such transitions in rotator ensembles. All the obtained analytical results are confirmed by the numerical ones, both by direct simulations of the large ensembles and by solution of the associated Fokker-Planck equation. We also propose generalizations of the developed approaches for setups where different rotators parameters (natural frequencies, masses, noise intensities, strengths and phase shifts in coupling) are dispersed.
KW  - coupled rotators
KW  - synchronization transition
KW  - hysteresis
KW  - Kuramoto
KW  - model
KW  - noisy systems
Y1  - 2020
U6  - https://doi.org/10.1088/1367-2630/ab6f93
SN  - 1367-2630
VL  - 22
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Munyaev, Vyacheslav
A1  - Smirnov, Lev A.
A1  - Kostin, Vasily
A1  - Osipov, Grigory V.
A1  - Pikovskij, Arkadij
T1  - Analytical approach to synchronous states of globally coupled noisy rotators
JF  - New Journal of Physics
N2  - We study populations of globally coupled noisy rotators (oscillators with inertia) allowing a nonequilibrium transition from a desynchronized state to a synchronous one (with the nonvanishing order parameter). The newly developed analytical approaches resulted in solutions describing the synchronous state with constant order parameter for weakly inertial rotators, including the case of zero inertia, when the model is reduced to the Kuramoto model of coupled noise oscillators. These approaches provide also analytical criteria distinguishing supercritical and subcritical transitions to the desynchronized state and indicate the universality of such transitions in rotator ensembles. All the obtained analytical results are confirmed by the numerical ones, both by direct simulations of the large ensembles and by solution of the associated Fokker-Planck equation. We also propose generalizations of the developed approaches for setups where different rotators parameters (natural frequencies, masses, noise intensities, strengths and phase shifts in coupling) are dispersed.
KW  - coupled rotators
KW  - synchronization transition
KW  - hysteresis
KW  - Kuramoto model
KW  - noisy systems
Y1  - 2019
VL  - 22
IS  - 2
PB  - Springer Science
CY  - New York
ER  - 
TY  - JOUR
A1  - Abdalla, H.
A1  - Adam, R.
A1  - Aharonian, Felix A.
A1  - Benkhali, F. Ait
A1  - Angüner, Ekrem Oǧuzhan
A1  - Arcaro, C.
A1  - Armand, C.
A1  - Armstrong, T.
A1  - Ashkar, H.
A1  - Backes, M.
A1  - Baghmanyan, V.
A1  - Martins, V. Barbosa
A1  - Barnacka, A.
A1  - Barnard, M.
A1  - Becherini, Y.
A1  - Berge, D.
A1  - Bernlohr, K.
A1  - Bi, B.
A1  - Bottcher, M.
A1  - Boisson, C.
A1  - Bolmont, J.
A1  - de Lavergne, M. de Bony
A1  - Bordas, Pol
A1  - Breuhaus, M.
A1  - Brun, F.
A1  - Brun, P.
A1  - Bryan, M.
A1  - Buchele, M.
A1  - Bulik, T.
A1  - Bylund, T.
A1  - Caroff, S.
A1  - Carosi, A.
A1  - Casanova, Sabrina
A1  - Chand, T.
A1  - Chandra, S.
A1  - Chen, A.
A1  - Cotter, G.
A1  - Curylo, M.
A1  - Mbarubucyeye, J. Damascene
A1  - Davids, I. D.
A1  - Davies, J.
A1  - Deil, C.
A1  - Devin, J.
A1  - deWilt, P.
A1  - Dirson, L.
A1  - Djannati-Atai, A.
A1  - Dmytriiev, A.
A1  - Donath, A.
A1  - Doroshenko, V.
A1  - Duffy, C.
A1  - Dyks, J.
A1  - Egberts, Kathrin
A1  - Eichhorn, F.
A1  - Einecke, S.
A1  - Emery, G.
A1  - Ernenwein, J. -P.
A1  - Feijen, K.
A1  - Fegan, S.
A1  - Fiasson, A.
A1  - de Clairfontaine, G. Fichet
A1  - Fontaine, G.
A1  - Funk, S.
A1  - Fussling, Matthias
A1  - Gabici, S.
A1  - Gallant, Y. A.
A1  - Giavitto, G.
A1  - Giunti, L.
A1  - Glawion, D.
A1  - Glicenstein, J. F.
A1  - Gottschall, D.
A1  - Grondin, M. -H.
A1  - Hahn, J.
A1  - Haupt, M.
A1  - Hermann, G.
A1  - Hinton, J. A.
A1  - Hofmann, W.
A1  - Hoischen, Clemens
A1  - Holch, T. L.
A1  - Holler, M.
A1  - Horbe, M.
A1  - Horns, D.
A1  - Huber, D.
A1  - Jamrozy, M.
A1  - Jankowsky, D.
A1  - Jankowsky, F.
A1  - Jardin-Blicq, A.
A1  - Joshi, V.
A1  - Jung-Richardt, I.
A1  - Kasai, E.
A1  - Kastendieck, M. A.
A1  - Katarzynski, K.
A1  - Katz, U.
A1  - Khangulyan, D.
A1  - Khelifi, B.
A1  - Klepser, S.
A1  - Kluzniak, W.
A1  - Komin, Nu.
A1  - Konno, R.
A1  - Kosack, K.
A1  - Kostunin, D.
A1  - Kreter, M.
A1  - Lamanna, G.
A1  - Lemiere, A.
A1  - Lemoine-Goumard, M.
A1  - Lenain, J. -P.
A1  - Levy, C.
A1  - Lohse, T.
A1  - Lypova, I.
A1  - Mackey, J.
A1  - Majumdar, J.
A1  - Malyshev, D.
A1  - Malyshev, D.
A1  - Marandon, V.
A1  - Marchegiani, P.
A1  - Marcowith, Alexandre
A1  - Mares, A.
A1  - Marti-Devesa, G.
A1  - Marx, R.
A1  - Maurin, G.
A1  - Meintjes, P. J.
A1  - Meyer, M.
A1  - Mitchell, A.
A1  - Moderski, R.
A1  - Mohamed, M.
A1  - Mohrmann, L.
A1  - Montanari, A.
A1  - Moore, C.
A1  - Morris, P.
A1  - Moulin, Emmanuel
A1  - Muller, J.
A1  - Murach, T.
A1  - Nakashima, K.
A1  - Nayerhoda, A.
A1  - de Naurois, M.
A1  - Ndiyavala, H.
A1  - Niederwanger, F.
A1  - Niemiec, J.
A1  - Oakes, L.
A1  - O'Brien, Patrick
A1  - Odaka, H.
A1  - Ohm, S.
A1  - Olivera-Nieto, L.
A1  - Wilhelmi, E. de Ona
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Panter, M.
A1  - Panny, S.
A1  - Parsons, R. D.
A1  - Peron, G.
A1  - Peyaud, B.
A1  - Piel, Q.
A1  - Pita, S.
A1  - Poireau, V.
A1  - Noel, A. Priyana
A1  - Prokhorov, D. A.
A1  - Prokoph, H.
A1  - Puhlhofer, G.
A1  - Punch, M.
A1  - Quirrenbach, A.
A1  - Raab, S.
A1  - Rauth, R.
A1  - Reichherzer, P.
A1  - Reimer, A.
A1  - Reimer, O.
A1  - Remy, Q.
A1  - Renaud, M.
A1  - Rieger, F.
A1  - Rinchiuso, L.
A1  - Romoli, C.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Ruiz-Velasco, E.
A1  - Sahakian, V.
A1  - Sailer, S.
A1  - Sanchez, D. A.
A1  - Santangelo, Andrea
A1  - Sasaki, M.
A1  - Scalici, M.
A1  - Schussler, F.
A1  - Schutte, H. M.
A1  - Schwanke, U.
A1  - Schwemmer, S.
A1  - Seglar-Arroyo, M.
A1  - Senniappan, M.
A1  - Seyffert, A. S.
A1  - Shafi, N.
A1  - Shiningayamwe, K.
A1  - Simoni, R.
A1  - Sinha, A.
A1  - Sol, H.
A1  - Specovius, A.
A1  - Spencer, S.
A1  - Spir-Jacob, M.
A1  - Stawarz, L.
A1  - Sun, L.
A1  - Steenkamp, R.
A1  - Stegmann, C.
A1  - Steinmassl, S.
A1  - Steppa, C.
A1  - Takahashi, T.
A1  - Tavernier, T.
A1  - Taylor, A. M.
A1  - Terrier, R.
A1  - Tiziani, D.
A1  - Tluczykont, M.
A1  - Tomankova, L.
A1  - Trichard, C.
A1  - Tsirou, M.
A1  - Tuffs, R.
A1  - Uchiyama, Y.
A1  - van der Walt, D. J.
A1  - van Eldik, C.
A1  - van Rensburg, C.
A1  - van Soelen, B.
A1  - Vasileiadis, G.
A1  - Veh, J.
A1  - Venter, C.
A1  - Vincent, P.
A1  - Vink, J.
A1  - Volk, H. J.
A1  - Vuillaume, T.
A1  - Wadiasingh, Z.
A1  - Wagner, S. J.
A1  - Watson, J.
A1  - Werner, F.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Wong, Yu Wun
A1  - Yusafzai, A.
A1  - Zacharias, M.
A1  - Zanin, R.
A1  - Zargaryan, D.
A1  - Zdziarski, A. A.
A1  - Zech, Alraune
A1  - Zhu, S. J.
A1  - Ziegler, A.
A1  - Zorn, J.
A1  - Zouari, S.
A1  - Zywucka, N.
T1  - An extreme particle accelerator in the Galactic plane
BT  - HESS J1826-130
JF  - Astronomy and astrophysics : an international weekly journal
N2  - The unidentified very-high-energy (VHE; E > 0.1 TeV) gamma -ray source, HESS J1826-130, was discovered with the High Energy Stereoscopic System (HESS) in the Galactic plane. The analysis of 215 h of HESS data has revealed a steady gamma -ray flux from HESS J1826-130, which appears extended with a half-width of 0.21 degrees +/- 0.02 <br /> (stat)degrees <br /> stat degrees +/- 0.05 <br /> (sys)degrees sys degrees . The source spectrum is best fit with either a power-law function with a spectral index Gamma = 1.78 +/- 0.10(stat) +/- 0.20(sys) and an exponential cut-off at 15.2 <br /> (+5.5)(-3.2) -3.2+5.5 TeV, or a broken power-law with Gamma (1) = 1.96 +/- 0.06(stat) +/- 0.20(sys), Gamma (2) = 3.59 +/- 0.69(stat) +/- 0.20(sys) for energies below and above E-br = 11.2 +/- 2.7 TeV, respectively. The VHE flux from HESS J1826-130 is contaminated by the extended emission of the bright, nearby pulsar wind nebula, HESS J1825-137, particularly at the low end of the energy spectrum. Leptonic scenarios for the origin of HESS J1826-130 VHE emission related to PSR J1826-1256 are confronted by our spectral and morphological analysis. In a hadronic framework, taking into account the properties of dense gas regions surrounding HESS J1826-130, the source spectrum would imply an astrophysical object capable of accelerating the parent particle population up to greater than or similar to 200 TeV. Our results are also discussed in a multiwavelength context, accounting for both the presence of nearby supernova remnants, molecular clouds, and counterparts detected in radio, X-rays, and TeV energies.
KW  - ISM: supernova remnants
KW  - ISM: clouds
KW  - gamma rays: general
KW  - gamma rays:
KW  - ISM
Y1  - 2020
U6  - https://doi.org/10.1051/0004-6361/202038851
SN  - 0004-6361
SN  - 1432-0746
VL  - 644
PB  - EDP Sciences
CY  - Les Ulis
ER  -