论文标题
具有离子电势的Haldane-Hubbard模型中的相变
Phase transitions in the Haldane-Hubbard model with ionic potentials
论文作者
论文摘要
通过采用精确的二进制方法，我们在蜂窝晶格上重新访问了带有交错的sublattice电位的haldane-Hubbard模型的地面相图。相图包括带绝缘子，Mott绝缘子和两个Chern绝缘体相，分别为Chern数字C = 2和C = 1。通过分析较低的能量水平，激发差距，结构因子和保真度度量来研究不同阶段之间的过渡特征。我们发现，在周期性边界条件下，C = 1相可以连续变形为C = 2相，而无需差距闭合，而对浆果曲率的进一步分析表明，激发差距在扭曲的边界条件下在相边界处关闭，伴随着结构因子的不连续性。所有其他相变为预期的一阶转换。
By employing the exact-diagonalization method, we revisit the ground-state phase diagram of the Haldane-Hubbard model on the honeycomb lattice with staggered sublattice potentials. The phase diagram includes the band insulator, Mott insulator, and two Chern insulator phases with Chern numbers C=2 and C=1, respectively. The character of transitions between different phases is studied by analyzing the lower-lying energy levels, excitation gaps, structure factors, and fidelity metric. We find that the C=1 phase can be continuously deformed into the C=2 phase without a gap closure in the periodic boundary condition, while a further analysis on the Berry curvatures indicates that the excitation gap closes at the phase boundary in a twisted boundary condition, accompanied by the discontinuities of structure factors. All the other phase transitions are found to be first-order ones as expected.
