Sublattice Interference in the Kagome Hubbard Model

TL;DR

This paper investigates how the kagome lattice structure influences electronic instabilities and superconductivity in the Hubbard model, revealing a sublattice interference mechanism that suppresses certain phases and enhances others.

Contribution

It introduces a sublattice interference mechanism affecting Fermi surface instabilities in the kagome Hubbard model, impacting superconductivity and potential exotic states.

Findings

Suppression of d+id superconductivity Tc due to sublattice interference

Increase of Tc with longer-range interactions

Potential for exotic electronic states at intermediate coupling

Abstract

We study the electronic phases of the kagome Hubbard model (KHM) in the weak coupling limit around van Hove filling. Through an analytic renormalization group analysis, we find that there exists a sublattice interference mechanism where the kagome sublattice structure affects the character of the Fermi surface instabilities. It leads to major suppression of Tc for d+id superconductivity in the KHM and causes an anomalous increase of Tc upon addition of longer-range Hubbard interactions. We conjecture that the suppression of conventional Fermi liquid instabilities makes the KHM a prototype candidate for hosting exotic electronic states of matter at intermediate coupling.