@misc{VarykhalovFreyseAguileraetal.2020,
  author    = {Varykhalov, Andrei and Freyse, Friedrich and Aguilera, Irene and Battiato, Marco and Krivenkov, Maxim and Marchenko, Dmitry and Bihlmayer, Gustav and Blugel, Stefan and Rader, Oliver and Sanchez-Barriga, Jaime},
  title     = {Effective mass enhancement and ultrafast electron dynamics of Au(111) surface state coupled to a quantum well},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-54989},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-549892},
  pages     = {11},
  year      = {2020},
  abstract  = {We show that, although the equilibrium band dispersion of the Shockley-type surface state of two-dimensional Au(111) quantum films grown on W(110) does not deviate from the expected free-electron-like behavior, its nonequilibrium energy-momentum dispersion probed by time- and angle-resolved photoemission exhibits a remarkable kink above the Fermi level due to a significant enhancement of the effective mass. The kink is pronounced for certain thicknesses of the Au quantum well and vanishes in the very thin limit. We identify the kink as induced by the coupling between the Au(111) surface state and emergent quantum-well states which probe directly the buried gold-tungsten interface. The signatures of the coupling are further revealed by our time-resolved measurements which show that surface state and quantum-well states thermalize together behaving as dynamically locked electron populations. In particular, relaxation of hot carriers following laser excitation is similar for both surface state and quantum-well states and much slower than expected for a bulk metallic system. The influence of quantum confinement on the interplay between elementary scattering processes of the electrons at the surface and ultrafast carrier transport in the direction perpendicular to the surface is shown to be the reason for the slow electron dynamics.},
  language  = {en}
}
@article{VarykhalovFreyseAguileraetal.2020,
  author    = {Varykhalov, Andrei and Freyse, Friedrich and Aguilera, Irene and Battiato, Marco and Krivenkov, Maxim and Marchenko, Dmitry and Bihlmayer, Gustav and Blugel, Stefan and Rader, Oliver and Sanchez-Barriga, Jaime},
  title     = {Effective mass enhancement and ultrafast electron dynamics of Au(111) surface state coupled to a quantum well},
  series = {Physical Review Research},
  volume    = {2},
  journal   = {Physical Review Research},
  number    = {1},
  publisher = {American Physical Society},
  address   = {Ridge, NY},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevResearch.2.013343},
  pages     = {1 -- 9},
  year      = {2020},
  abstract  = {We show that, although the equilibrium band dispersion of the Shockley-type surface state of two-dimensional Au(111) quantum films grown on W(110) does not deviate from the expected free-electron-like behavior, its nonequilibrium energy-momentum dispersion probed by time- and angle-resolved photoemission exhibits a remarkable kink above the Fermi level due to a significant enhancement of the effective mass. The kink is pronounced for certain thicknesses of the Au quantum well and vanishes in the very thin limit. We identify the kink as induced by the coupling between the Au(111) surface state and emergent quantum-well states which probe directly the buried gold-tungsten interface. The signatures of the coupling are further revealed by our time-resolved measurements which show that surface state and quantum-well states thermalize together behaving as dynamically locked electron populations. In particular, relaxation of hot carriers following laser excitation is similar for both surface state and quantum-well states and much slower than expected for a bulk metallic system. The influence of quantum confinement on the interplay between elementary scattering processes of the electrons at the surface and ultrafast carrier transport in the direction perpendicular to the surface is shown to be the reason for the slow electron dynamics.},
  language  = {en}
}
@article{SajediKrivenkovMarchenkoetal.2022,
  author    = {Sajedi, Maryam and Krivenkov, Maxim and Marchenko, Dmitry and Sanchez-Barriga, Jaime and Chandran, Anoop K. and Varykhalov, Andrei and Rienks, Emile D. L. and Aguilera, Irene and Bl{\"u}gel, Stefan and Rader, Oliver},
  title     = {Is there a polaron signature in Angle-Resolved Photoemission of CsPbBr3?},
  series = {Physical review letters},
  volume    = {128},
  journal   = {Physical review letters},
  number    = {17},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.128.176405},
  pages     = {7},
  year      = {2022},
  abstract  = {The formation of large polarons has been proposed as reason for the high defect tolerance, low mobility, low charge carrier trapping, and low nonradiative recombination rates of lead halide perovskites. Recently, direct evidence for large-polaron formation has been reported from a 50\% effective mass enhancement in angle-resolved photoemission of CsPbBr3 over theory for the orthorhombic structure. We present in-depth band dispersion measurements of CsPbBr3 and GW calculations, which lead to similar effective masses at the valence band maximum of 0.203 1 0.016 m0 in experiment and 0.226 m0 in orthorhombic theory. We argue that the effective mass can be explained solely on the basis of electron-electron correlation and largepolaron formation cannot be concluded from photoemission data.},
  language  = {en}
}