Bose-Fermi-Hubbard model on a lattice with two nonequivalent sublattices

Abstract

Phase transitions in systems described by Bose-Fermi-Hubbard model on a lattice with two nonequivalent sublattices are investigated in this work. The case of hard-core bosons is considered and pseudospin formalism is used. Phase diagrams are built in the plain of chemical potential of the bosons-bosonic hopping parameter. It is shown that in the case of anisotropic hopping, the region of the supersolid phase existence is possible for a smaller parameter space.

Fermion Spectrum Of Bose-Fermi-Hubbard Model In The Phase With Bose-Einstein Condensate

“…The mixtures of ultracold bosons and spin-polarized fermions in optical lattices are well described by the Bose-Fermi-Hubbard Hamiltonian [8][9][10]…”

“…In theoretical investigations, the mixture of Bose-Fermi atoms in optical lattices was studied within the Bose-Fermi-Hubbard model (BFHM) [3][4][5][6][7][8][9]. According to the model, the key role in the MI-SF phase transitions belongs to the interplay between the tendency to a localization at the lattice sites and the short-range interaction between particles, as well as the intersite particle hopping.…”

“…The case of hard-core bosons was considered, and the pseudospin formalism was used to describe the phase transitions at finite temperatures in the Bose--Fermi--Hubbard model in the self-consistent random phase approximation [8] and the mean-field ap-proximation for a lattice with two nonequivalent sublattices [9]. It was shown in those works that the transitions between the uniform and charge-ordered phases can be of the second or first order, depending on parameters of the system.…”