@article{07676a7f31b94ce681923ce203b458a8,
title = "Temperature and magnetic field dependent raman study of electron-phonon interactions in thin films of bi2se3 and bi2te3 nanoflakes",
abstract = "We have investigated two-dimensional nanostructures of the topological insulators Bi2Se3 and Bi2Te3 by means of temperature and magnetic field dependent Raman spectroscopy. The surface contribution of our samples was increased by using thin films of dropcasted nanoflakes with the aim of enhancing their topological properties. Raman spectroscopy provides a contact-free method to investigate the behavior of topological properties with temperature and magnetic fields at lower dimensions. The temperature dependent Raman study reveals anharmonic phonon behavior for Bi2Te3 indicative of a two-phonon relaxation mechanism in this material. Contrary to this, Bi2Se3 shows clear deviations from a two-phonon anharmonic decay model at temperatures below 120 K exhibiting a hardening and broadening, especially of the A1g2 mode. Similarly, the magnetic field dependent self-energy effects are only observed for the A1g2 mode of Bi2Se3, showing a broadening and hardening with increasing field. We interpret our results in terms of corrections to the phonon self-energy for Bi2Se3 at temperatures below 120 K and magnetic fields above 4 T due to electron-hole pair excitations associated with the conducting surface states. The phonon renormalization with increasing magnetic field is explained by a gap opening in the Dirac cone that enables phonon coupling to the changing electric susceptibility.",
author = "S{\"o}ren Buchenau and Sarah Scheitz and Astha Sethi and Slimak, {John E.} and Glier, {Tomke Eva} and Das, {Pranab Kumar} and Torben Dankwort and Lewis Akinsinde and Lorenz Kienle and Andrivo Rusydi and Clemens Ulrich and Cooper, {S. Lance} and Michael R{\"u}bhausen",
note = "Funding Information: This work was funded by the Deutsche Forschungsgemeinschaft (DFG; German Research Foundation), DFG RU 773/8-1. Work at the University of Illinois was supported by the National Science Foundation under Grant No. NSF DMR 1800982. S.B., C.U., and M.R. would like to acknowledge the support from the Australian Research Council (ARC) through Grant No. DP170100415. The work at National University of Singapore is supported by the Ministry of Educations of Singapore AcRF Tier-2 (Grants No. MOE2017-T2-1-135, No. 323 MOE2018-T2-2-117, and No. MOE2018-T2-2-117), and Ministry of Education AcRF-1 (Grant No. R-144-000-423-114) and is acknowledged by the support of the Singapore Synchrotron Light Source (SSLS), which is a National Research Infrastructure under the National Research Foundation Singapore via NUS Core Support Grant No. C-380-003-003-001. We thank Robert Fr{\"o}mter and Dorota Koziej for the use of their scanning electron microscopes. We are further thankful for Robert Zierold and Stephan Martens for helpful discussions and magnetization measurements of our samples. Publisher Copyright: {\textcopyright} 2020 American Physical Society.",
year = "2020",
month = jun,
day = "15",
doi = "10.1103/PhysRevB.101.245431",
language = "English (US)",
volume = "101",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Physical Society",
number = "24",
}