The demixing of the two-component fermions in optical lattices under a spin-dependent external potential

TL;DR

This paper investigates how two-component fermions in optical lattices separate under a spin-dependent external potential, mapping the phase diagram and identifying conditions for phase separation and core formation.

Contribution

It provides a detailed numerical phase diagram of demixing behavior influenced by on-site interactions and external potential ratios, revealing the formation of insulating cores.

Findings

Identified a phase boundary with a minimum point.

Found insulating core formation in spin-up densities during demixing.

Mapped the phase diagram distinguishing phase-mixed and phase-separated regions.

Abstract

The demixing of two-component fermions in optical lattices under a spin-dependent external potential is investigated using the density-matrix renormalization group method. The influence of on-site interactions (u) and the ratio of the spin-dependent external potentials ($\gamma$) on the demixing is discussed. The $\gamma-u$ state diagram is numerically mapped out, from which we distinguish the phase-mixed region from the phase-separated one. A minimum point appears in the phase boundary. On the right part of the point an insulating core is formed in the spin-up densities during the demixing, while on the left one only metallic phase exists.