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Title: What makes the T c of monolayer FeSe on SrTiO 3 so high: a sign-problem-free quantum Monte Carlo study

Monolayer FeSe films grown on SrTiO 3 (STO) substrate show superconducting gap-opening temperatures (T c) which are almost an order of magnitude higher than those of the bulk FeSe and are highest among all known Fe-based superconductors. Angle-resolved photoemission spectroscopy observed “replica bands” suggesting the importance of the interaction between FeSe electrons and STO phonons. These facts rejuvenated the quest for T c enhancement mechanisms in iron-based, especially iron-chalcogenide, superconductors. Here, we perform the first numerically-exact sign-problem-free quantum Monte Carlo simulations to iron-based superconductors. We (1) study the electronic pairing mechanism intrinsic to heavily electron doped FeSe films, and (2) examine the effects of electron–phonon interaction between FeSe and STO as well as nematic fluctuations on T c. Armed with these results, we return to the question “what makes the T c of monolayer FeSe on SrTiO 3 so high?” in the conclusion and discussions.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Tsinghua Univ., Beijing (China). Inst. for Advanced Study
  2. Peking Univ., Beijing (China). International Center for Quantum Materials. School of Physics; Collaborative Innovation Center of Quantum Matter, Beijing (China)
  3. Tsinghua Univ., Beijing (China). Inst. for Advanced Study; Collaborative Innovation Center of Quantum Matter, Beijing (China)
  4. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
Publication Date:
Grant/Contract Number:
AC02-05CH11231; 11474175; 11374018
Type:
Accepted Manuscript
Journal Name:
Science Bulletin
Additional Journal Information:
Journal Volume: 61; Journal Issue: 12; Journal ID: ISSN 2095-9273
Publisher:
Elsevier; Science China Press
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Tsinghua Univ., Beijing (China)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Natural Science Foundation of China (NNSFC)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; high temperature superconductivity; pairing mechanism; iron-based superconductivity; FeSe/STO; sign-problem-free quantum Monte-Carlo simulation
OSTI Identifier:
1414758