发表机构
Institute of Theoretical Physics, Jagiellonian University（雅盖隆大学理论物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过SGA方法构建含RSOC的$t$-$J$-$U$模型相图，发现关联驱动的$C=\pm2$拓扑超导态及变磁转变，揭示关联与RSOC联合效应的重要性。
AI 中文摘要
非常规超导电性通常出现在具有强电子关联的系统中，层状铜氧化物便是典型例子。在铋系铜氧化物中观察到自旋-动量锁定现象，这与存在不可忽略的Rashba型自旋-轨道耦合（RSOC）相符，因此需要研究电子关联与RSOC对铜氧化物及相关超导体中配对效应的联合影响。采用统计一致变分近似（SGA），我们通过构建包含RSOC的方格$t$-$J$-$U$模型的相图进行了此类分析。我们还研究了塞曼场破坏时间反演对称性的效应，并刻画了涌现的拓扑超导（TSC）态。在接近半填充的宽泛局域库仑排斥区间内，发现了陈数$C = \pm 4$的TSC态。该态不受关联支配，在弱耦合Bogoliubov-de Gennes（BdG）方案中同样出现。然而，我们识别出一种独特的$C = \pm 2$ TSC态，该态由电子关联专门驱动，通过一种体准粒子能隙不闭合的拓扑转变实现，并伴随不连续的变磁和Lifshitz转变。此外，我们展示了在金属-绝缘体转变之上，底层混合宇称超导序参量的$d$波和$p$波分量具有定性不同的掺杂演化。我们的工作表明，在BdG方案之外，关联与RSOC的联合效应对RSOC耦合超导体的相图具有重要意义。
英文摘要
Unconventional superconductivity commonly emerges in systems characterized by strong electronic correlations, with layered copper-oxides serving as a canonical example. Observation of spin-momentum locking within Bi-family of the cuprates, compatible with the presence of non-negligible Rashba-type spin-orbit coupling (RSOC), calls for an investigation of the joint effects of electronic correlations and RSOC on pairing in copper-oxide and related superconductors. Employing statistically-consistent variational approximation (SGA), we carry out such an analysis by constructing the phase diagram for the case of square-lattice \textit{t-J-U} model incorporating RSOC. We also investigate the effects of time-reversal-symmetry breaking by Zeeman field, as well as characterize emergent topological superconducting (TSC) states. Chern number $C = \pm 4$ TSC is found in a broad regime of on-site Coulomb repulsion close to half-filling. The latter is not governed by correlations and emerges also within the weak-coupling Bogoliubov-de Gennes (BdG) scheme. Yet, we identify a distinct $C = \pm 2$ TSC state that is driven specifically by electronic correlations via a topological transition occurring with no bulk quasiparticle gap closure, and is accompanied by discontinuous metamagnetic and Lifshitz transitions. Moreover, a qualitatively distinct doping evolution of the $d$- and $p$-wave components of the underlying mixed-parity SC order parameter above the metal-to-insulator transition is demonstrated. Our work points toward the relevance of joint correlation and RSOC effects beyond BdG scheme to phase diagrams of RSOC-coupled superconductors.
