Advantages of Mass-Imbalanced Ultracold Fermionic Mixtures for Approaching Quantum Magnetism in Optical Lattices

TL;DR

This paper investigates how mass imbalance in ultracold fermionic mixtures enhances the realization and detection of quantum magnetic phases in optical lattices, using advanced theoretical methods.

Contribution

It introduces the study of mass-imbalanced mixtures with repulsive interactions in optical lattices, revealing their advantages for observing quantum magnetism.

Findings

Mass imbalance leads to charge-density wave signatures alongside Néel order.

Mass-imbalanced mixtures can achieve magnetic order at higher temperatures.

Regions identified where imbalanced mixtures outperform balanced ones for quantum magnetism detection.

Abstract

We study magnetic phases of two-component mixtures of ultracold fermions with repulsive interactions in optical lattices in the presence of hopping imbalance. Our analysis is based on dynamical mean-field theory (DMFT) and its real-space generalization at finite temperature. We study the temperature dependence of the transition into the ordered state as a function of the interaction strength and the imbalance parameter in two and three spatial dimensions. We show that below the critical temperature for N\'{e}el order mass-imbalanced mixtures also exhibit a charge-density wave, which provides a directly observable signature of the ordered state. For the trapped system, we compare our results obtained by real-space DMFT to a local-density approximation. We calculate the entropy for a wide range of parameters and identify regions, in which mass-imbalanced mixtures could have clear advantages over balanced ones for the purpose of obtaining and detecting quantum magnetism.