Superconductivity, pseudogap, and phase separation in topological flat bands: a quantum Monte Carlo study
Abstract
We study a two-dimensional model of an isolated narrow topological band at partial filling with local attractive interactions. Numerically exact quantum Monte Carlo calculations show that the ground state is a superconductor with a critical temperature that scales nearly linearly with the interaction strength. We also find a broad pseudogap regime at temperatures above the superconducting phase that exhibits strong pairing fluctuations and a tendency towards electronic phase separation; introducing a small nearest neighbor attraction suppresses superconductivity entirely and results in phase separation. We discuss the possible relevance of superconductivity in this unusual regime to the physics of flat band moir\'{e} materials, and as a route to designing higher temperature superconductors.
Cite
@article{arxiv.1912.08848,
title = {Superconductivity, pseudogap, and phase separation in topological flat bands: a quantum Monte Carlo study},
author = {Johannes S. Hofmann and Erez Berg and Debanjan Chowdhury},
journal= {arXiv preprint arXiv:1912.08848},
year = {2020}
}
Comments
We now also include weak nearest-neighbor attractive interactions and find phase separation instead of superconductivity (new Fig. 4)