Physical Review B
Finite-temperature phase diagram of the three-dimensional hard-core bosonic t - J model
Yuki Nakano, Takumi Ishima, Naohiro Kobayashi, Kazuhiko Sakakibara, Ikuo Ichinose, Tetsuo Matsui
Abstract
We study the three-dimensional bosonic $t$-$J$ model, that is, the $t$-$J$ model of ``bosonic electrons'' at finite temperatures. This model describes a system of an isotropic antiferromagnet with doped bosonic holes and is closely related to systems of two-component bosons in an optical lattice. The bosonic ``electron'' operator ${B}_{x\ensuremath{\sigma}}$ at the site $x$ with a two-component spin $\ensuremath{\sigma}(=$$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 (CP${}^{1}$ boson) ${z}_{x\ensuremath{\sigma}}$ and a holon described by a hard-core-boson field ${\ensuremath{\phi}}_{x}$ as ${B}_{x\ensuremath{\sigma}}={\ensuremath{\phi}}_{x}^{\ifmmode\dagger\else\textdagger\fi{}}{z}_{x\ensuremath{\sigma}}$. By means of Monte Carlo simulations of this bosonic $t$-$J$ model, we study its phase structure and the possible phenomena like appearance of antiferromagnetic long-range order, Bose-Einstein condensation, phase separation, etc. Obtained results show that the bosonic $t$-$J$ model has a phase diagram that suggests some interesting implications for high-temperature superconducting materials.