标题： 扭曲过渡金属二硫属化物双层带中暗激子的长寿命超流体特性 显示英文标题

标题： Long-living superfluidity of dark excitons in a strip of strained transition metal dichalcogenides double layer

摘要： 我们提出了双层过渡金属硫属化物（TMDC）异质结构带状结构中偶极子激子的超流性。 我们展示了应变会导致导带底和价带顶在k空间中发生偏移。 因此，我们预计在该系统中施加应变可以产生暗激子。 我们数值计算了拉伸的MoSe$_2$中暗偶极子激子的能量谱，并计算了它们的结合能和有效质量。 我们证明了拉伸TMDC异质结构中的暗偶极子激子会形成超流体，并计算了集体激发能量谱中的声速以及超流体的平均场临界温度。 我们展示了系统中两股反向移动的独立超流体流会在条带的两边各出现一层，形成双层结构。 我们观察到超流体的临界温度随着暗激子浓度的增加以及层间间距的增大而升高。 暗激子不能通过简单的光子发射衰减这一事实，使得由它们形成的超流体和凝聚体比由亮激子形成的具有更长的寿命。 我们提出了一种实验验证预测现象的方法。 显示英文摘要

摘要： We have proposed the superfluidity of dipolar excitons in a strip of double-layer transition metal dichalcogenides (TMDCs) heterostructures. We have shown that strain causes a shift in k-space between the minimum of the conduction band and the maximum of the valence band. Therefore, we expect that applying strain to this system can cause dark excitons to be created. We have numerically calculated the energy spectrum of dark dipolar excitons in strained MoSe$_2$, and we have calculated their binding energies and effective masses. We have shown that the dark dipolar excitons in strained TMDC heterostructures form superfluids, and we have calculated the sound velocity in the energy spectrum of collective excitations, as well as the mean-field critical temperature for superfluidity. We have shown that two separate superfluid flows moving in opposite directions will appear in the system, one on each edge of the strip, forming the double layer. We have seen that the critical temperature for superfluidity increases with the concentration of dark excitons, as well as with the inter-layer separation. The fact that dark excitons cannot decay by the simple emission of photons, makes it so that the superfluids and condensates formed by them have a much longer lifetime than that formed by bright excitons. We propose a way to experimentally verify the predicted phenomena.