Edge-induced strongly correlated electronic states in two-dimensional Hubbard model: Enhancement of magnetic correlations and self-energy effects

TL;DR

This study investigates how open edges in two-dimensional Hubbard models influence electronic states, revealing enhanced magnetic correlations and potential edge-driven phenomena like superconductivity and quantum criticality.

Contribution

It demonstrates the edge-induced enhancement of spin susceptibilities and predicts novel edge phenomena in strongly correlated electron systems using FLEX approximation.

Findings

Strong spin susceptibility enhancement near the edge at half-filling

Edge regions exhibit potential for edge superconductivity and quantum criticality

Self-energy effects do not suppress the edge magnetic enhancement

Abstract

To understand nontrivial edge electronic states in strongly-correlated metals such as cuprate superconductors, we study the two-dimensional Hubbard models with open edge boundary. The position-dependences of the spin susceptibility and the self-energy are carefully analyzed self-consistently, by using the fluctuation-exchange (FLEX) approximation. It is found that spin susceptibilities are strongly enlarged near the (1,1) open edge when the system is near the half-filling. The enhancement is large even if the negative feedback from the self-energy is considered in the FLEX approximation. The present study predicts the emergence of nontrivial spin-fluctuation-driven phenomena near the edge, like the quantum criticality, edge superconductivity, and the bond-density-wave order.