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Title: Gigantic Surface Lifetime of an Intrinsic Topological Insulator

We report that the interaction between light and novel two-dimensional electronic states holds promise to realize new fundamental physics and optical devices. Here, we use pump-probe photoemission spectroscopy to study the optically excited Dirac surface states in the bulk-insulating topological insulator Bi2Te2Se and reveal optical properties that are in sharp contrast to those of bulk-metallic topological insulators. We observe a gigantic optical lifetime exceeding 4 μs (1 μs=10$${-}$$6 s) for the surface states in Bi2Te2Se, whereas the lifetime in most topological insulators, such as Bi2Se3, has been limited to a few picoseconds (1 ps=10$${-}$$12 s). Moreover, we discover a surface photovoltage, a shift of the chemical potential of the Dirac surface states, as large as 100 mV. Lastly, our results demonstrate a rare platform to study charge excitation and relaxation in energy and momentum space in a two-dimensional system.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2] ;  [2] ;  [2] ;  [2] ;  [6] ;  [7] ;  [3] ;  [8] ;  [9]
  1. Princeton Univ., NJ (United States). Joseph Henry Lab., Dept. of Physics; Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Princeton Univ., NJ (United States). Joseph Henry Lab., Dept. of Physics
  3. Univ. of Tokyo (Japan). Inst. for Solid State Physics (ISSP)
  4. Princeton Univ., NJ (United States). Dept. of Chemistry; Peking Univ., Beijing (China). International Center for Quantum Materials
  5. Univ. of California, Berkeley, CA (United States). Dept. of Physics
  6. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  7. Univ. of Maryland, College Park, MD (United States). Joint Quantum Inst. and Condensed Matter Theory Center, Dept. of Physics; Monash Univ., Melbourne, VIC (Australia). School of Physics
  8. Princeton Univ., NJ (United States). Dept. of Chemistry
  9. Princeton Univ., NJ (United States). Joseph Henry Lab., Dept. of Physics; Princeton Univ., NJ (United States). Princeton Center for Complex Materials
Publication Date:
OSTI Identifier:
1334115
Report Number(s):
LA-UR--15-26947
Journal ID: ISSN 0031-9007; PRLTAO
Grant/Contract Number:
AC52-06NA25396; FG-02-05ER46200; AC03-76SF00098; FG02-07ER46352; SC0001911; AC02-05CH11231; GBMF4547; 26800165; DMR 1206513;
Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 115; Journal Issue: 11; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); LDRD; NSF; Australian Research Council; Simons Foundation
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE Topological Insulators; pump probe; ARPES