Mean-field phase diagram of the Bose-Fermi Hubbard model
Abstract
We analyze the ground-state properties of mixtures consisting of scalar bosons and spin-1/2 fermions using a mean-field treatment of the local boson-fermion interaction on a simple cubic lattice. In the deep superfluid limit of the boson sector and the BCS regime of the fermion sector, we derive BCS-type equations to determine the phase diagram of the system. We find a competition between a charge density wave and a superconducting phase. In the opposite limit, we study the Mott-insulator-to-superfluid transition of the boson sector in the presence of a staggered density-induced alternating potential provided by the fermions, and determine the mean-field transition line. In the two-superfluids phase of the mixture, we restrict to nearest-neighbor-induced interactions between the fermions and consider the extended Hubbard model. We perform a mean-field analysis of the critical temperature for the formation of boson-assisted s-, extended s--, d-, and p-wave pairs at fermionic half-filling. We compare our results with a recent dynamical mean-field study [P. Anders et al., Phys. Rev. Lett. 109, 206401 (2012), 10.1103/PhysRevLett.109.206401].
- Publication:
-
Physical Review B
- Pub Date:
- March 2014
- DOI:
- 10.1103/PhysRevB.89.094502
- arXiv:
- arXiv:1311.7148
- Bibcode:
- 2014PhRvB..89i4502B
- Keywords:
-
- 67.85.Pq;
- 71.10.Fd;
- Mixtures of Bose and Fermi gases;
- Lattice fermion models;
- Condensed Matter - Quantum Gases
- E-Print:
- 13 pages, 4 figures