Insulator phases of Bose-Fermi mixtures induced by intraspecies next-neighbor interactions

TL;DR

This paper investigates how intraspecies next-neighbor interactions influence the ground states of a one-dimensional Bose-Fermi mixture, revealing new insulating phases with unique charge density wave structures and phase relationships.

Contribution

It introduces the effects of non-local intraspecies interactions on insulating phases and identifies three novel charge density wave states with specific phase characteristics.

Findings

Non-local interactions can promote or suppress known Mott insulators.

Discovery of three new charge density wave insulating states.

Identification of phase relationships and order parameters for each state.

Abstract

We study a one-dimensional mixture of two-color fermions and scalar bosons at the hardcore limit, focusing on the effect that the intraspecies next-neighbor interactions have on the zero-temperature ground state of the system for different fillings of each carrier. Exploring the problem's parameters, we observed that the non-local interaction could favor or harm the well-known mixed Mott and spin-selective Mott insulators. We also found the emergence of three unusual insulating states with charge density wave (CDW) structures in which the orders of the carriers are out of phase with each other. For instance, the immiscible CDW appears only at half-filling bosonic density, whereas the mixed CDW state is characterized by equal densities of bosons and fermions. Finally, the spin-selective CDW couples the bosons and only one kind of fermions. Appropriate order parameters were proposed for each phase to obtain the critical parameters for the corresponding superfluid-insulator transition. Our results can inspire or contribute to understanding experiments in cold-atom setups with long-range interactions or recent reports involving quasiparticles in semiconductor heterostructures.