Thermodynamic properties of two-component fermionic atoms trapped in a two-dimensional optical lattice

TL;DR

This paper investigates the thermodynamic behavior of two-component fermionic atoms in a 2D optical lattice, revealing phase crossovers and magnetic transitions influenced by trapping potentials.

Contribution

It applies the self-energy functional approach to analyze the 2D Hubbard model with trapping potential, providing new insights into phase transitions and magnetic ordering.

Findings

Entropy indicates crossover between Mott insulator and metal.

Entropy shows cusp-like anomaly at low temperatures.

Trapping potential influences antiferromagnetic transition temperatures.

Abstract

We study the finite temperature properties of two-component fermionic atoms trapped in a two-dimensional optical lattice. We apply the self-energy functional approach to the two-dimensional Hubbard model with a harmonic trapping potential, and systematically investigate the thermodynamic properties of this system. We find that entropy and grand potential provide evidence of a crossover between the Mott insulating and metallic phases at certain temperatures. In addition, we find that entropy exhibits a cusp-like anomaly at lower temperatures, suggesting a second or higher order antiferromagnetic transition. We estimate the antiferromagnetic transition temperatures, and clarify how the trapping potential affects this magnetic transition.