Metal-Insulator-Superconductor transition of spin-3/2 atoms on optical lattices

TL;DR

This paper investigates the phase transitions among metallic, Mott-insulating, and superconducting states of spin-3/2 atoms in optical lattices, revealing a novel superconducting phase with unique symmetry-breaking properties.

Contribution

It introduces a new superconducting phase arising from spin-3/2 interactions, expanding understanding of quantum phases in optical lattice systems.

Findings

Identification of a novel superconducting phase breaking both roton and spinon gauge symmetries.

Distinction between two superconducting phases via quasiparticle weight.

Analysis of phase properties across 2D and 3D lattices at various temperatures.

Abstract

We use a slave-rotor approach within a mean-field theory to study the competition of metallic, Mott-insulating, and superconducting phases of spin-3/2 fermions subjected to a periodic optical lattice potential. In addition to the metallic, the Mott-insulating, and the superconducting phases that are associated with the gauge symmetry breaking of the spinon field, we identify a novel emerging superconducting phase that breaks both roton and spinon field gauge symmetries. This novel superconducting phase emerges as a result of the competition between spin-0 singlet and spin-2 quintet interaction channels naturally available for spin-3/2 systems. The two superconducting phases can be distinguished from each other by quasiparticle weight. We further discuss the properties of these phases for both two-dimensional square and three-dimensional cubic lattices at zero and finite temperatures.