Correlated phases of population imbalanced Fermi-Fermi mixtures on an optical lattice

Article

关键词: RENORMALIZATION-GROUP APPROACH;    HUBBARD-MODEL;    SUPERCONDUCTIVITY;    GAS;    INSTABILITIES;    SUPERFLUIDITY;   

DOI  :  10.1103/PhysRevB.87.075134

来源: SCIE

【 摘 要 】

We study a two-species fermion mixture with different populations on a square lattice modeled by a Hubbard Hamiltonian with onsite interspecies repulsive interaction. Such a model can be realized in a cold-atom system with fermionic atoms in two different hyperfine states loaded on an optical lattice and with tunable interspecies interaction strength via external fields. For a two-dimensional square lattice, when at least one of the fermion species is close to half-filling, the system is highly affected by lattice effects. With the majority species near half-filling and varying densities for the minority species, we find that several correlated phases emerge as the ground state, including a spin density wave state, a charge density wave state with stripe structure, and various p-wave BCS pairing states for both species. We study this system using a functional renormalization group method, determine its phase diagram at weak coupling, discuss the origin and characteristics of each phase, and provide estimates for the critical temperatures. DOI: 10.1103/PhysRevB.87.075134

【 授权许可】

Free