Incommensurate nematic fluctuations in the two-dimensional Hubbard model

TL;DR

This paper investigates nematic fluctuations in the 2D Hubbard model, revealing incommensurate diagonal modulations above Van Hove filling and the influence of extended interactions, with nematic fluctuations being subdominant to other orders.

Contribution

It provides a detailed analysis of incommensurate nematic fluctuations using renormalization group methods in the extended Hubbard model.

Findings

Nematic fluctuations are incommensurate and diagonal above Van Hove filling.

Extended interactions enhance nematic fluctuations but do not dominate.

Nematic fluctuations are always smaller than antiferromagnetic, pairing, or charge density wave fluctuations.

Abstract

We analyze effective d-wave interactions in the two-dimensional extended Hubbard model at weak coupling and small to moderate doping. The interactions are computed from a renormalization group flow. Attractive d-wave interactions are generated via antiferromagnetic spin fluctuations in the pairing and charge channels. Above Van Hove filling, the d-wave charge interaction is maximal at incommensurate diagonal wave vectors, corresponding to nematic fluctuations with a diagonal modulation. Below Van Hove filling a modulation along the crystal axes can be favored. The nematic fluctuations are enhanced by the nearest-neighbor interaction in the extended Hubbard model, but they always remain smaller than the dominant antiferromagnetic, pairing, or charge density wave fluctuations.