Finite-temperature valence-bond-solid transitions and thermodynamic properties of interacting SU(2N) Dirac fermions | |
Article | |
关键词: OPTICAL LATTICE; MOTT INSULATOR; SPIN; SYSTEMS; LIQUID; PHASES; GASES; ATOMS; | |
DOI : 10.1103/PhysRevB.95.085128 | |
来源: SCIE |
【 摘 要 】
We investigate the SU(2N) symmetry effects with 2N > 2 on the two-dimensional interacting Dirac fermions at finite temperatures, including the valence-bond-solid transition, the Pomeranchuk effect, the compressibility, and the uniform spin susceptibility, by performing the determinant quantum Monte Carlo simulations of the half-filled SU(2N) Hubbard model on a honeycomb lattice. The columnar valence-bond-solid (cVBS) phase only breaks the threefold discrete symmetry and thus can survive at finite temperatures. The disordered phase in the weak coupling regime is the thermal Dirac semi-metal state, while in the strong coupling regime it is largely a Mott state in which the cVBS order is thermally melted. The calculated entropy-temperature relations for various values of the Hubbard interaction U show that the Pomeranchuk effect occurs when the specific entropy is below a characteristic value of S*-the maximal entropy per particle from the spin channel of local moments. The SU(2N) symmetry enhances the Pomeranchuk effect, which facilitates the interaction-induced adiabatic cooling. Our work sheds light on future explorations of novel states of matter with ultracold large-spin alkaline fermions.
【 授权许可】
Free