Finite-temperature phase diagram of two-component bosons in a cubic optical lattice: Three-dimensional t-J model of hard-core bosons

الأصل · EN

We study the three-dimensional bosonic t-J model, i.e., the t-J model of "bosonic electrons", at finite temperatures. This model describes the s=1 2 Heisenberg spin model with the anisotropic exchange coupling J=-αJz and doped bosonic holes, which is an effective system of the Bose-Hubbard model with strong repulsions. The bosonic "electron" operator Bᵣσ at the site r with a two-component (pseudo-)spin σ(=1,2) is treated as a hard-core boson operator, and represented by a composite of two slave particles; a "spinon" described by a Schwinger boson (CP¹ boson) zᵣσ and a "holon" described by a hard-core-boson field ϕᵣ as Bᵣσ=ϕ†ᵣ zᵣσ. By means of Monte Carlo simulations, we study its finite-temperature phase structure including the α dependence, the possible phenomena like appearance of checkerboard long-range order, super-counterflow, superfluid, and phase separation, etc. The obtained results may be taken as predictions about experiments of two-component cold bosonic atoms in the cubic optical lattice.