论文标题
二维有吸引力的费米 - 哈伯德模型中的相图，带结构和状态的密度与rashba旋转轨道耦合
Phase diagram, band structure and density of states in two-dimensional attractive Fermi-Hubbard model with Rashba spin-orbit coupling
论文作者
论文摘要
基于与Rashba自旋轨道耦合（SOC）的二维（2D）有吸引力的费米 - 哈伯德模型，可以通过自我一致地计算配对差距来研究相图的SOC强度和Zeeman场依赖性。结果表明，在适当的Zeeman野外强度和SOC强度下发生了从BCS超流体到拓扑超流体的相过渡。特别是，与BCS超流量随着SOC强度的增加而单调降低的相反，拓扑超流体区域显示出圆顶，随着SOC强度的增加。可以找到相图中找到拓扑超流体的最佳区域，这对于实验中的光学晶格中实现拓扑超流体很重要。然后，我们通过拓扑相变的状态结构和状态密度（DOS）的变化，并通过拓扑超流体中的DOS的四个峰通过准粒子能量光谱的低能分支的拓扑变化来解释DOS的四个峰。此外，可以通过掺杂浓度来抑制拓扑超流体。
Based on the two-dimensional (2D) attractive Fermi-Hubbard model with Rashba spin-orbit coupling (SOC), the SOC strength and Zeeman field dependences of the phase diagram are investigated by calculating the pairing gap self-consistently. The results reveal that the phase transition from the BCS superfluid to the topological superfluid happens under proper Zeeman field strength and SOC strength. In particular, in contrast to the BCS superfluid decreasing monotonically as the SOC strength increasing, the topological superfluid region shows a dome with the SOC strength increasing. An optimal region in the phase diagram to find the topological superfluid can be found, which is important to realize the topological superfluid in optical lattice experimentally. Then we obtain the change of both band structure and density of states (DOS) during the topological phase transition, and explain the four peaks of DOS in the topological superfluid by the topology change of the low-energy branch of quasiparticle energy spectra. Moreover, the topological superfluid can be suppressed by the doping concentration.
