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Title: Surface Collective Modes in the Topological Insulators Bi 2 Se 3 and Bi 0.5 Sb 1.5 Te 3 - x Se x

Abstract

We used low-energy, momentum-resolved inelastic electron scattering to study surface collective modes of the three-dimensional topological insulators Bi 2 Se 3 and Bi 0.5 Sb 1.5 Te 3 - x Se x . Our goal was to identify the “spin plasmon” predicted by Raghu and co-workers [Phys. Rev. Lett. 104, 116401 (2010)]. Instead, we found that the primary collective mode is a surface plasmon arising from the bulk, free carriers in these materials. This excitation dominates the spectral weight in the bosonic function of the surface χ '' ( q , ω ) at THz energy scales, and is the most likely origin of a quasiparticle dispersion kink observed in previous photoemission experiments. Our study suggests that the spin plasmon may mix with this other surface mode, calling for a more nuanced understanding of optical experiments in which the spin plasmon is reported to play a role

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Emergent Superconductivity (CES)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1387306
DOE Contract Number:  
AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 115; Journal Issue: 25; Related Information: CES partners with Brookhaven National Laboratory (BNL); Argonne National Laboratory; University of Illinois, Urbana-Champaign; Los Alamos National Laboratory
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; phonons, thermal conductivity, energy storage (including batteries and capacitors), superconductivity, defects, spin dynamics

Citation Formats

Kogar, A., Vig, S., Thaler, A., Wong, M. H., Xiao, Y., Reig-i-Plessis, D., Cho, G. Y., Valla, T., Pan, Z., Schneeloch, J., Zhong, R., Gu, G. D., Hughes, T. L., MacDougall, G. J., Chiang, T. -C., and Abbamonte, P. Surface Collective Modes in the Topological Insulators Bi2Se3 and Bi0.5Sb1.5Te3-xSex. United States: N. p., 2015. Web. doi:10.1103/PhysRevLett.115.257402.
Kogar, A., Vig, S., Thaler, A., Wong, M. H., Xiao, Y., Reig-i-Plessis, D., Cho, G. Y., Valla, T., Pan, Z., Schneeloch, J., Zhong, R., Gu, G. D., Hughes, T. L., MacDougall, G. J., Chiang, T. -C., & Abbamonte, P. Surface Collective Modes in the Topological Insulators Bi2Se3 and Bi0.5Sb1.5Te3-xSex. United States. doi:10.1103/PhysRevLett.115.257402.
Kogar, A., Vig, S., Thaler, A., Wong, M. H., Xiao, Y., Reig-i-Plessis, D., Cho, G. Y., Valla, T., Pan, Z., Schneeloch, J., Zhong, R., Gu, G. D., Hughes, T. L., MacDougall, G. J., Chiang, T. -C., and Abbamonte, P. Tue . "Surface Collective Modes in the Topological Insulators Bi2Se3 and Bi0.5Sb1.5Te3-xSex". United States. doi:10.1103/PhysRevLett.115.257402.
@article{osti_1387306,
title = {Surface Collective Modes in the Topological Insulators Bi2Se3 and Bi0.5Sb1.5Te3-xSex},
author = {Kogar, A. and Vig, S. and Thaler, A. and Wong, M. H. and Xiao, Y. and Reig-i-Plessis, D. and Cho, G. Y. and Valla, T. and Pan, Z. and Schneeloch, J. and Zhong, R. and Gu, G. D. and Hughes, T. L. and MacDougall, G. J. and Chiang, T. -C. and Abbamonte, P.},
abstractNote = {We used low-energy, momentum-resolved inelastic electron scattering to study surface collective modes of the three-dimensional topological insulators Bi 2 Se 3 and Bi 0.5 Sb 1.5 Te 3 - x Se x . Our goal was to identify the “spin plasmon” predicted by Raghu and co-workers [Phys. Rev. Lett. 104, 116401 (2010)]. Instead, we found that the primary collective mode is a surface plasmon arising from the bulk, free carriers in these materials. This excitation dominates the spectral weight in the bosonic function of the surface χ '' ( q , ω ) at THz energy scales, and is the most likely origin of a quasiparticle dispersion kink observed in previous photoemission experiments. Our study suggests that the spin plasmon may mix with this other surface mode, calling for a more nuanced understanding of optical experiments in which the spin plasmon is reported to play a role},
doi = {10.1103/PhysRevLett.115.257402},
journal = {Physical Review Letters},
number = 25,
volume = 115,
place = {United States},
year = {Tue Dec 01 00:00:00 EST 2015},
month = {Tue Dec 01 00:00:00 EST 2015}
}