Quantum phases of a Two-Dimensional Dipolar Fermi Gas

TL;DR

This paper investigates the phase diagram of a two-dimensional dipolar Fermi gas, revealing conditions for stable superfluidity driven by anisotropic interactions and analyzing the transition temperature at finite temperatures.

Contribution

It demonstrates how anisotropic dipolar interactions enable stable superfluid phases without collapse in a 2D Fermi gas, and calculates the BKT transition temperature.

Findings

Stable superfluid phase exists over a broad parameter range.

Effective interaction can be enhanced without causing collapse.

BKT transition temperature depends on dipole orientation.

Abstract

We examine the superfluid and collapse instabilities of a quasi two-dimensional gas of dipolar fermions aligned by an orientable external field. It is shown that the interplay between the anisotropy of the dipolar interaction, the geometry of the system, and the p-wave symmetry of the superfluid order parameter means that the effective interaction for pairing can be made very large without the system collapsing. This leads to a broad region in the phase diagram where the system forms a stable superfluid. Analyzing the superfluid transition at finite temperatures, we calculate the Berezinskii--Kosterlitz--Thouless temperature as a function of the dipole angle.