Robustness of flat band superconductivity against disorder in a two-dimensional Lieb lattice model

TL;DR

This paper demonstrates that flat-band superconductivity in a 2D Lieb lattice model is surprisingly resilient to disorder, with critical temperature reductions being significantly less severe than in conventional superconductors, potentially easing material purity constraints.

Contribution

It reveals the robustness of flat-band superconductivity against disorder and quantifies how critical temperature decreases with disorder strength in a Lieb lattice model.

Findings

Critical temperature decreases quadratically with disorder in flat-band SC.

Flat-band SC is more robust to disorder than conventional SC.

Disorder impact is less severe in flat-band systems, enabling easier material synthesis.

Abstract

Recently, the possibility of high-temperature superconductivity (SC) in flat-band (FB) systems has been the focus of a great deal of activity. This study reveals that unlike conventional intra-band SC for which disorder has a dramatic impact, that associated with FBs is surprisingly robust to disorder-induced fluctuations and quasi-particle localization. In particular, for weak off-diagonal disorder, the critical temperature decreases linearly with disorder amplitude for conventional SC, whereas it is only quadratic in the case of SC in FBs. Our findings could have a major impact on the research and development of new compounds whose high purity will no longer be a critical barrier to their synthesis.