Formation of Electronic Nematic Phase in Interacting Systems

TL;DR

This paper investigates how electronic nematic phases form in interacting fermion systems, revealing the nature of phase transitions and their dependence on interaction strength, temperature, and electronic dispersion.

Contribution

It provides a theoretical analysis of the phase transition from isotropic Fermi liquids to nematic phases, including the conditions for first and second order transitions and their suppression of Lifshitz transitions.

Findings

First order transition at zero temperature for all dispersions.

Second order transition at finite temperature.

Nematic phase formation at arbitrarily small interactions at van Hove filling.

Abstract

We study the formation of an electronic nematic phase characterized by a broken point-group symmetry in interacting fermion systems within the weak coupling theory. As a function of interaction strength and chemical potential, the phase transition between the isotropic Fermi liquid and nematic phase is first order at zero temperature and becomes second order at a finite temperature. The transition is present for all typical, including quasi-2D, electronic dispersions on the square lattice and takes place for arbitrarily small interaction when at van Hove filling, thus suppressing the Lifshitz transition. In connection with the formation of the nematic phase, we discuss the origin of the first order transition and competition with other broken symmetry states.