Spin-selective insulators

TL;DR

This paper reviews spin-selective insulators, a novel phase where one fermion species remains gapless while another becomes insulating, especially in Bose-Fermi mixtures relevant for cold atom experiments.

Contribution

It provides a comprehensive overview of the mechanisms and conditions leading to spin-selective insulators, emphasizing recent developments in cold atom systems.

Findings

Identification of conditions for spin-selective insulating states

Analysis of Bose-Fermi mixture scenarios

Potential for experimental realization in cold atom setups

Abstract

Spin-selective insulators emerge in systems composed of fermions with two internal degrees of freedom and another carrier, which could be fermionic or bosonic. These insulators are characterized by a gapless state for one kind of fermion and an insulator state for the other, with the latter satisfying a commensurability relation that involves the other carrier. We review the different scenarios where these unique insulators arise, focusing on Bose-Fermi mixtures, the most recent and promising scenario for observing these insulators in cold atom setups.