TY  - JOUR
A1  - Dzhigaev, D.
A1  - Shabalin, A.
A1  - Stankevic, T.
A1  - Lorenz, Ulf
A1  - Kurta, R. P.
A1  - Seiboth, F.
A1  - Wallentin, J.
A1  - Singer, A.
A1  - Lazarev, S.
A1  - Yefanov, O. M.
A1  - Borgstrom, M.
A1  - Strikhanov, M. N.
A1  - Samuelson, L.
A1  - Falkenberg, G.
A1  - Schroer, C. G.
A1  - Mikkelsen, A.
A1  - Vartanyants, I. A.
T1  - Bragg coherent x-ray diffractive imaging of a single indium phosphide nanowire
JF  - Journal of optics
N2  - Three-dimensional (3D) Bragg coherent x-ray diffractive imaging (CXDI) with a nanofocused beam was applied to quantitatively map the internal strain field of a single indium phosphide nanowire. The quantitative values of the strain were obtained by pre-characterization of the beam profile with transmission ptychography on a test sample. Our measurements revealed the 3D strain distribution in a region of 150 nm below the catalyst Au particle. We observed a slight gradient of the strain in the range of +/- 0.6% along the [111] growth direction of the nanowire. We also determined the spatial resolution in our measurements to be about 10 nm in the direction perpendicular to the facets of the nanowire. The CXDI measurements were compared with the finite element method simulations and show a good agreement with our experimental results. The proposed approach can become an effective tool for in operando studies of the nanowires.
KW  - Bragg coherent x-ray diffractive imaging
KW  - InP nanowires
KW  - strain field
Y1  - 2016
U6  - https://doi.org/10.1088/2040-8978/18/6/064007
SN  - 2040-8978
SN  - 2040-8986
VL  - 18
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Schmidt, Burkhard
A1  - Lorenz, Ulf
T1  - WavePacket
BT  - a Matlab package for numerical quantum dynamics. I: Closed quantum systems and discrete variable representations
JF  - Computer physics communications : an international journal devoted to computational physics and computer programs in physics
N2  - WavePacket is an open-source program package for the numerical simulation of quantum-mechanical dynamics. It can be used to solve time-independent or time-dependent linear Schrödinger and Liouville–von Neumann-equations in one or more dimensions. Also coupled equations can be treated, which allows to simulate molecular quantum dynamics beyond the Born–Oppenheimer approximation. Optionally accounting for the interaction with external electric fields within the semiclassical dipole approximation, WavePacket can be used to simulate experiments involving tailored light pulses in photo-induced physics or chemistry. The graphical capabilities allow visualization of quantum dynamics ‘on the fly’, including Wigner phase space representations. Being easy to use and highly versatile, WavePacket is well suited for the teaching of quantum mechanics as well as for research projects in atomic, molecular and optical physics or in physical or theoretical chemistry. The present Part I deals with the description of closed quantum systems in terms of Schrödinger equations. The emphasis is on discrete variable representations for spatial discretization as well as various techniques for temporal discretization. The upcoming Part II will focus on open quantum systems and dimension reduction; it also describes the codes for optimal control of quantum dynamics. The present work introduces the MATLAB version of WavePacket 5.2.1 which is hosted at the Sourceforge platform, where extensive Wiki-documentation as well as worked-out demonstration examples can be found.
KW  - Schrodinger equation
KW  - Quantum dynamics
KW  - Numerical propagation
KW  - Bound states
KW  - Discrete variable representation
KW  - Non-adiabatic transitions
Y1  - 0207
U6  - https://doi.org/10.1016/j.cpc.2016.12.007
SN  - 0010-4655
SN  - 1879-2944
VL  - 213
SP  - 223
EP  - 234
PB  - Elsevier
CY  - Amsterdam
ER  -