Magnetic and superfluid phases of confined fermions in two-dimensional optical lattices

TL;DR

This paper investigates the coexistence and shell structures of antiferromagnetic and superfluid phases in confined two-dimensional optical lattices of cold fermionic atoms, revealing how these phases compete and can be experimentally detected.

Contribution

It provides a detailed analysis of phase coexistence, shell structures, and detection methods in a realistic experimental setup with repulsive fermions in optical lattices.

Findings

Coexistence of magnetic and superfluid phases in trapped fermionic gases.

Shell structures depend on filling fraction and phase competition.

Detection of phases via density-density correlation functions.

Abstract

We examine antiferromagnetic and d-wave superfluid phases of cold fermionic atoms with repulsive interactions in a two-dimensional optical lattice combined with a harmonic trapping potential. For experimentally realistic parameters, the trapping potential leads to the coexistence of magnetic and superfluid ordered phases with the normal phase. We study the intriguing shell structures arising from the competition between the magnetic and superfluid order as a function of the filling fraction. In certain cases antiferromagnetism induce superfluidity by charge redistributions. We furthermore demonstrate how these shell structures can be detected as distinct anti-bunching dips and pairing peaks in the density-density correlation function probed in expansion experiments.