论文标题
T-J模型中的手性和淋巴结超导体在三角形的Moiré晶格上与山谷对比磁通
Chiral and nodal superconductors in t-J model with valley contrasting flux on triangular moiré lattice
论文作者
论文摘要
最近的实验进展使模拟由过渡金属二色ogogenide（TMD）杂词形成的Moiré材料中的三角形晶格模拟自旋1/2 Hubbard模型。在扭曲的TMD同型物体中，垂直电场可以在跳跃期间诱导山谷对比的通量。在本文中，我们使用从属玻色子均值磁场理论研究了带有山谷对比磁通$φ$的T-J模型的可能超导体。我们获得了带有掺杂$ x $和$φ$的相图。有限的$φ$断裂旋转旋转对称性，配对对称性是旋转旋风$ d-id $和旋转三重态的叠加$ p+ip $。将$φ$从$ 0 $到$π$调整$φ$时，有两个拓扑相变，一个dirac节点有一个过渡，另一个在另一个过渡时进行了一个dirac节点。我们还讨论了Van Hove奇异性的影响以及三个站点相关的跳跃术语对配对强度的影响。最后，我们证明了一个小的各向异性术语打破$ C_3 $旋转会导致连接到$ d_ {x^2-y^2} $ Square Lattice上的$ d_ {x^2-y^2} $超导体的时间逆转不变的节点超导体。
Recent experimental progresses have made it possible to simulate spin 1/2 Hubbard model on triangular lattice in moiré materials formed by transition metal dichalcogenide (TMD) heterobilayer or homobilayer. In twisted TMD homobilayer, a vertical electric field can induce a valley contrasting flux in the hopping term. In this paper we study possible superconductors from a t-J model with valley contrasting flux $Φ$ using the slave boson mean field theory. We obtain a phase diagram with doping $x$ and $Φ$. A finite $Φ$ breaks spin rotation symmetry and the pairing symmetry is a superposition of spin singlet $d-id$ and spin triplet $p+ip$. There are two topological phase transitions when tuning $Φ$ from $0$ to $π$, with three Dirac nodes at one transition and one single Dirac node at the other transition. We also discuss the effects of van Hove singularity and a three-site correlated hopping term on the pairing strength. Lastly, we demonstrate that a small anisotropy term breaking the $C_3$ rotation can lead to a time reversal invariant nodal superconductor connected to the $d_{x^2-y^2}$ superconductor on square lattice.
