论文标题
Rashba-Hubbard模型中强烈的平均混合超导性
Strongly parity-mixed superconductivity in Rashba-Hubbard model
论文作者
论文摘要
包含强相关电子系统的异质结构提供了一个平台，以阐明非常规超导体中电子相关性和Rashba自旋轨道耦合的相互作用。通过最近制造的人工设计的重费用超级晶格和高温铜酸盐超导体的动机，我们对Rashba-Hubbard模型中的超导性进行了详尽的研究。与以前的弱耦合方法相反，我们采用了波动 - 交换近似来描述量子临界磁波动和产生的超导性。结果，稳健的费米表面可抵抗磁波动，不超增量的自旋波动以及强烈混合的超导阶段，在从II型范霍夫型奇异性到半填充的各种电子填充中被证明。我们还阐明了II型Van Hove奇点对磁波动和超导性的影响。而$ d_ {x^2-y^2} $ - 波配对始终占主导地位，次级旋转三个旋转式搭配与$ p $ - 波或$ f $ - 波 - 波 - 波 - 对称性对称性显示出可比的幅度，尤其是在II型Van Hove Hove Singularity附近。我们的结果解决了在密切相关的RASHBA系统上的未解决问题，并发现了非肾脏运输和拓扑超导性的候选系统。
Heterostructures containing strongly correlated electron systems provide a platform to clarify interplay of electron correlation and Rashba spin-orbit coupling in unconventional superconductors. Motivated by recent fabrication of artificially-engineered heavy fermion superlattices and high-temperature cuprate superconductors, we conduct a thorough study on superconductivity in Rashba-Hubbard model. In contrast to previous weak coupling approaches, we employ fluctuation-exchange approximation to describe quantum critical magnetic fluctuations and resulting superconductivity. As a result, robust Fermi surfaces against magnetic fluctuations, incommensurate spin fluctuations, and a strongly parity-mixed superconducting phase are demonstrated in a wide range of electron filling from type-II van Hove singularity to half-filling. We also clarify impacts of type-II van Hove singularity on magnetic fluctuations and superconductivity. Whereas the $d_{x^2-y^2}$-wave pairing always dominant, subdominant spin-triplet pairing with either $p$-wave or $f$-wave symmetry shows a comparable magnitude, especially near the type-II van Hove singularity. Our results resolve unsettled issues on strongly correlated Rashba systems and uncover candidate systems of nonreciprocal transport and topological superconductivity.
