Quantum nematic as ground state of a two-dimensional electron gas in a magnetic field

TL;DR

This paper investigates the quantum nematic phase in a two-dimensional electron gas at filling fraction 1/2, showing it can be the ground state under certain conditions using variational wavefunctions and approximation methods.

Contribution

It introduces a variational wavefunction with Jastrow correlations and elliptical Fermi sea to analyze the nematic phase's stability in quantum Hall systems.

Findings

Nematic phase is energetically favorable below a critical symmetry-breaking parameter.

Quantum nematic is favored over stripe Wigner crystal below a critical layer thickness.

The study identifies conditions under which the nematic phase emerges as the ground state.

Abstract

We study the ground state of a nematic phase of the two-dimensional electron gas at filling fraction $\nu = 1/2$ using a variational wavefunction having Jastrow pair-correlations of the form $\Pi_{i < j}(z_i-z_j)^2$ and an elliptical Fermi sea. Using the Fermi hypernetted chain approximation we find that below a critical value of the broken symmetry parameter, the nematic phase is energetically favorable as compared to the isotropic state for the second excited Landau level. We also find that below a critical value of the layer ``thickness'' parameter $\lambda$ (and in the actual materials) the quantum nematic is energetically favorable relative to the stripe ordered Wigner crystal phase.