论文标题
与自旋轨道耦合的扩展哈伯德模型中的一阶和二阶拓扑超导和温度驱动的拓扑相变
First- and Second-Order Topological Superconductivity and Temperature-Driven Topological Phase Transitions in the Extended Hubbard Model with Spin-Orbit Coupling
论文作者
论文摘要
自旋轨道耦合与相互作用的结合导致了许多外来物质阶段。在这封信中,我们调查了二维扩展哈伯德模型的超导配对不稳定性,在零和有限温度下,在平均场水平均与Rashba和Dresselhaus旋转轨道耦合均具有Rashba和Dresselhaus自旋轨道耦合。我们发现,在适当的参数和温度状态下,由于存在偏爱的均匀级别$ s+id $ - 即使在没有外部磁场或固有磁性的情况下,也可以在适当的参数和温度状态下实现一阶和二阶的对称对称性差距。这会导致每个边缘上的手性majorana边缘状态的两个分支,或在样品的每个角落一个零能量的Majorana角状状态。有趣的是,我们还发现,调整掺杂水平不仅会导致这两个不同的拓扑间隙阶段之间的直接拓扑相变,而且还将温度用作高度可控且可逆的调谐旋钮会导致不同的直接温度驱动的拓扑相变,从而导致间隙和无间隙的拓扑拓扑超导相关阶段。我们的发现提出了通过在简单但现实的显微镜模型中统一一阶和高阶拓扑超导体来统一一阶和高阶拓扑超导体的新可能性。
The combination of spin-orbit coupling with interactions results in many exotic phases of matter. In this Letter, we investigate the superconducting pairing instability of the two-dimensional extended Hubbard model with both Rashba and Dresselhaus spin-orbit coupling within the mean-field level at both zero and finite temperature. We find that both first- and second-order time-reversal symmetry breaking topological gapped phases can be achieved under appropriate parameters and temperature regimes due to the presence of a favored even-parity $s+id$-wave pairing even in the absence of an external magnetic field or intrinsic magnetism. This results in two branches of chiral Majorana edge states on each edge or a single zero-energy Majorana corner state at each corner of the sample. Interestingly, we also find that not only does tuning the doping level lead to a direct topological phase transition between these two distinct topological gapped phases, but also using the temperature as a highly controllable and reversible tuning knob leads to different direct temperature-driven topological phase transitions between gapped and gapless topological superconducting phases. Our findings suggest new possibilities in interacting spin-orbit coupled systems by unifying both first- and higher-order topological superconductors in a simple but realistic microscopic model.