Enhancement of critical temperatures in disordered bipartite lattices

TL;DR

This paper demonstrates how disorder can significantly increase critical temperatures for superconductivity, charge-density waves, and antiferromagnetism in bipartite lattices like graphene, using an advanced theoretical approach.

Contribution

It introduces an extended Finkel'stein non-linear sigma-model renormalization group method to analyze disorder effects on critical temperatures in bipartite lattice models.

Findings

Superconducting critical temperature can be arbitrarily enhanced by disorder.

Disorder induces antiferromagnetic order at high temperatures.

Superconductivity remains robust against Anderson localization.

Abstract

We study the strong enhancement, induced by random hopping, of the critical temperatures characterizing the transitions to superconductivity, charge-density wave and antiferromagnetism, which can occur in bipartite lattice models at half-filling, like graphene, by means of an extended Finkel'stein non-linear $\sigma$-model renormalization group approach. We show that, if Cooper channel interaction dominates, superconducting critical temperature can be enhanced at will, since superconductivity cannot be broken by entering any Anderson insulating phase. If, instead, staggered interactions are relevant, antiferromagnetic order is generated by disorder at a temperature well above that expected for a clean system.