论文标题
强相关的量子自旋霍尔绝缘子中的激子凝结
Exciton condensation in strongly correlated quantum spin Hall insulators
论文作者
论文摘要
时间逆转对称拓扑绝缘子在弱局部相互作用方面通常是鲁棒的，除非发生对称性断裂过渡。使用动态平均场理论，我们解决了量子自旋霍尔绝缘子的相互作用模型，并在中间耦合时表明了对称性断裂过渡到以激子凝结为特征的非探针绝缘体的存在。这种过渡是一阶。对于更大的相互作用强度，绝缘体会演变成莫特。如果防止磁性顺序，尤其是，对于任何有限的Hund的交换而言，它是连续的，它通过Mott的定位进行，然后再降低冷凝水相干性。我们表明，相关的激子状态对应于磁电绝缘子，该绝缘子允许直接实验探测。最后，我们讨论了跨激发型转变的螺旋边缘模式的命运。
Time reversal symmetric topological insulators are generically robust with respect to weak local interaction, unless symmetry breaking transitions take place. Using dynamical mean-field theory we solve an interacting model of quantum spin Hall insulators and show the existence, at intermediate coupling, of a symmetry breaking transition to a non-topological insulator characterised by exciton condensation. This transition is of first order. For a larger interaction strength the insulator evolves into a Mott one. The transition is continuous if magnetic order is prevented, and notably, for any finite Hund's exchange it progresses through a Mott localization before the condensate coherence is lost. We show that the correlated excitonic state corresponds to a magneto-electric insulator which allows for direct experimental probing. Finally, we discuss the fate of the helical edge modes across the excitonic transition.
