Ground-state properties of fermionic mixtures with mass imbalance in optical lattices

TL;DR

This paper investigates the ground-state properties of fermionic mixtures with mass imbalance in a one-dimensional optical lattice using the Falicov-Kimball model, revealing phase separation, coexistence of phases, density waves, and universal density variance behavior.

Contribution

It provides a detailed numerical analysis of mass-imbalanced fermionic mixtures in optical lattices, highlighting new phenomena such as phase separation and universal density variance.

Findings

Phase separation with heavy atoms at the center

Coexistence of Mott-insulating and metallic phases

Universal behavior of local density variance

Abstract

Ground-state properties of fermionic mixtures confined in a one-dimensional optical lattice are studied numerically within the spinless Falicov-Kimball model with a harmonic trap. A number of remarkable results are found. (i) At low particle filling the system exhibits the phase separation with heavy atoms in the center of the trap and light atoms in the surrounding regions. (ii) Mott-insulating phases always coexist with metallic phases. (iii) Atomic-density waves are observed in the insulating regions for all particle fillings near half-filled lattice case. (iv) The variance of the local density exhibits the universal behavior (independent of the particle filling, the Coulomb interaction and the strength of a confining potential) over the whole region of the local density values.