论文标题
Moiréising超导体中的轨道fulde-ferrell配对状态
Orbital Fulde-Ferrell pairing state in moiré Ising superconductors
论文作者
论文摘要
在这项工作中，我们研究了Moiré同型过渡金属二分裂元素的超导导向，其中Ising自旋轨道耦合（SOC）比Moiré带宽大得多。我们称这种非中心对称超导体，MoiréIsing超导体。由于较大的Ising SoC，由Zeeman场引起的降低效应可以忽略不计，并且平面上临界场（$ b_ {c2} $）由轨道效应确定。这使我们能够研究大轨道田的影响。有趣的是，当应用的平面内字段大于传统的轨道$ b_ {c2} $时，会出现有限的摩托车配对阶段，我们称之为轨道fulde-ferrell（ff）状态。在这种状态下，库珀对获得了$ 2Q_B $的净动量，其中$ 2Q_B = EBD $是由磁场$ b $和$ d $造成的动量转移，表示该图层分离。这种轨道野外驱动的FF状态与Rashba超导体中的Zeeman效应驱动的常规FF状态不同。值得注意的是，我们预测，当诱导层不对称时，FF配对将导致电控态下的巨大超导二极管效应。 $ b_ {c2} $的上升，随着温度降低，与巨大的超导二极管效应相结合，将允许检测轨道FF状态。
In this work, we study superconducting moiré homobilayer transition metal dichalcogenides where the Ising spin-orbit coupling (SOC) is much larger than the moiré bandwidth. We call such noncentrosymmetric superconductors, moiré Ising superconductors. Due to the large Ising SOC, the depairing effect caused by the Zeeman field is negligible and the in-plane upper critical field ($B_{c2}$) is determined by the orbital effects. This allows us to study the effect of large orbital fields. Interestingly, when the applied in-plane field is larger than the conventional orbital $B_{c2}$, a finite-momentum pairing phase would appear which we call the orbital Fulde-Ferrell (FF) state. In this state, the Cooper pairs acquire a net momentum of $2q_B$ where $2q_B=eBd$ is the momentum shift caused by the magnetic field $B$ and $d$ denotes the layer separation. This orbital field-driven FF state is different from the conventional FF state driven by Zeeman effects in Rashba superconductors. Remarkably, we predict that the FF pairing would result in a giant superconducting diode effect under electric gating when layer asymmetry is induced. An upturn of the $B_{c2}$ as the temperature is lowered, coupled with the giant superconducting diode effect, would allow the detection of the orbital FF state.
