Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Transport: Topological Insulators - 3D
(Joint session of DS, HL, MA, O and TT organized by TT)
TT 32.4: Vortrag
Dienstag, 8. März 2016, 15:00–15:15, H18
Electron-Phonon Interaction in Surface States of Topological Insulators from First Principles — •Rolf Heid1, Irina Yu. Sklyadneva2, and Eugine V. Chulkov2 — 1Institut für Festkörperphysik, Karlsruher Institut für Technologie — 2Donostia International Physics Center (DICP), San Sebastian/Donostia, Spain
Transport through the metallic 2D surface states of 3D topological insulators with a Dirac-like dispersion is controlled by many-body interactions. In particular, a large electron-phonon interaction could be a limiting factor for applications at elevated temperatures [1]. Previous experimental investigations of the coupling constant remained inconclusive as they found large variations ranging from <0.1 to 3 [2].
Here we present a first principles investigation of the electron-phonon interaction in surface states of topological insulators within density-functional perturbation theory including spin-orbit interaction [3], using Bi2Se3, Bi2Te3, and Sb2Te2S as prominent examples. We discuss the various challenges faced by this approach, such as the rather deep penetration of the surface state and the small momentum range of both electronic and phonon states relevant for the coupling. We find that the coupling strength exhibits a significant dependence on the binding energy, following essentially the available electronic phase space. We further investigate the variation of the coupling with doping to mimic typical experimental conditions.
[1] D. Kim et al., PRL 109, 166801 (2012)
[2] X. Zhu et al., arXiv: 1307.4559
[3] R. Heid et al., PRB 81, 174527 (2010)