Superconductivity and nematic fluctuations in a model of doped FeSe monolayers: Determinant quantum Monte Carlo study Journal Article


Author(s): Dumitrescu, Philipp T; Serbyn, Maksym; Scalettar, Richard T; Vishwanath, Ashvin K
Article Title: Superconductivity and nematic fluctuations in a model of doped FeSe monolayers: Determinant quantum Monte Carlo study
Affiliation
Abstract: In contrast to bulk FeSe, which exhibits nematic order and low temperature superconductivity, highly doped FeSe reverses the situation, having high temperature superconductivity appearing alongside a suppression of nematic order. To investigate this phenomenon, we study a minimal electronic model of FeSe, with interactions that enhance nematic fluctuations. This model is sign problem free, and is simulated using determinant quantum Monte Carlo (DQMC). We developed a DQMC algorithm with parallel tempering, which proves to be an efficient source of global updates and allows us to access the region of strong interactions. Over a wide range of intermediate couplings, we observe superconductivity with an extended s-wave order parameter, along with enhanced, but short-ranged, q=(0,0) ferro-orbital (nematic) order. These results are consistent with approximate weak-coupling treatments that predict that nematic fluctuations lead to superconducting pairing. Surprisingly, in the parameter range under study, we do not observe nematic long-range order. Instead, at stronger coupling an unusual insulating phase with q=(π,π) antiferro-orbital order appears, which is missed by weak-coupling approximations.
Journal Title: Physical Review B
Volume: 94
Issue 15
ISSN: 1550-235X
Publisher: American Physical Society  
Date Published: 2016-10-17
URL:
DOI: 10.1103/PhysRevB.94.155127
Notes: We thank S. Gazit for numerous discussions. This research was supported by the Gordon and Betty Moore Foundation EPiQS Initiative through Grant No. GBMF4307 (M.S.), the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Grant No. DE-SC0014671 (R.T.S.), and a Simons Investigator grant (A.V.).
Open access: yes (repository)