title: What makes theTcof monolayer FeSe on SrTiO3so high: a sign-problem-free quantum Monte Carlo study.
abstract: Monolayer FeSe films grown on SrTiO3(STO) substrate show superconducting gap-opening temperatures ([Formula: see text]) 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 [Formula: see text] 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 [Formula: see text]. Armed with these results, we return to the question "what makes the [Formula: see text] of monolayer FeSe on SrTiO3so high?" in the conclusion and discussions.
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing, 100084 China.
authors.forename: Zi-Xiang
authors.initials: ZX
authors.lastname: Li
authors.affiliation: International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871 China ; Collaborative Innovation Center of Quantum Matter, Beijing, 100871 China.
authors.forename: Fa
authors.initials: F
authors.lastname: Wang
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing, 100084 China ; Collaborative Innovation Center of Quantum Matter, Beijing, 100871 China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yao
authors.affiliation: Department of Physics, University of California, Berkeley, CA 94720 USA ; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA.
authors.forename: Dung-Hai
authors.initials: DH
authors.lastname: Lee
keywords: FeSe/STO; High temperature superconductivity; Iron-based superconductivity; Pairing mechanism; Sign-problem-free quantum Monte-Carlo simulation