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Title: Electronic structure and relaxation dynamics in a superconducting topological material

Topological superconductors host new states of quantum matter which show a pairing gap in the bulk and gapless surface states providing a platform to realize Majorana fermions. Recently, alkaline-earth metal Sr intercalated Bi2Se3 has been reported to show superconductivity with a Tc~3K and a large shielding fraction. Here we report systematic normal state electronic structure studies of Sr0.06Bi2Se3 (Tc~2.5K) by performing photoemission spectroscopy. Using angle-resolved photoemission spectroscopy (ARPES), we observe a quantum well confined two-dimensional (2D) state coexisting with a topological surface state in Sr0.06Bi2Se3. Furthermore, our time-resolved ARPES reveals the relaxation dynamics showing different decay mechanism between the excited topological surface states and the two-dimensional states. Our experimental observation is understood by considering the intra-band scattering for topological surface states and an additional electron phonon scattering for the 2D states, which is responsible for the superconductivity. Our first-principles calculations agree with the more effective scattering and a shorter lifetime of the 2D states. In conclusion, our results will be helpful in understanding low temperature superconducting states of these topological materials.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [5] ;  [5] ;  [6] ;  [7] ;  [3] ;  [5] ;  [4]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Central Florida, Orlando, FL (United States)
  2. Univ. of Tokyo (Japan)
  3. National Taiwan Univ., Taipei (Taiwan)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. Princeton Univ., NJ (United States)
  6. Univ. of Central Florida, Orlando, FL (United States)
  7. Univ. of Tokyo (Japan); National Taiwan Univ., Taipei (Taiwan)
Publication Date:
OSTI Identifier:
1259464
Grant/Contract Number:
FG-02-05ER46200; AC03-76SF00098; FG02-07ER46352
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY