Berry-Flux-Controlled Cascade of Chiral Superconducting States
Moscow Institute of Physics and Technology（莫斯科物理技术学院）；Landau Institute for Theoretical Physics（朗道理论物理研究所）；California Institute of Technology（加州理工学院）；Massachusetts Institute of Technology（麻省理工学院）
受近期对窄带中手性超导性的兴趣启发，我们建立了一个通用框架，以阐明能带拓扑和量子几何如何影响超导配对并关联到两体问题。Berry曲率不仅有利于手性配对通道，还产生一系列由角动量标记的手性配对不稳定性，这些不稳定性由费米海中的Berry通量控制，在动量空间中具有类似Little-Parks的周期性。我们证明，Berry曲率将非手性吸引相互作用转化为动量空间中的几何受挫库珀问题。相关控制参数是费米海包围的Berry曲率通量$Φ= b k_F^2$，它作为定义在费米面上的序参量的有效Aharonov-Bohm通量。随着$Φ$的调节，主导配对不稳定性在奇角动量通道$m=1,3,5...$之间切换，产生一系列一级相变和$T_c$的类似Little-Parks的振荡。
英文摘要：
Motivated by recent interest in chiral superconductivity in narrow bands, we develop a general framework to clarify how band topology and quantum geometry affect superconducting pairing and connect to the two-body problem. Berry curvature does not merely favor a chiral pairing channel; it produces a sequence of chiral pairing instabilities indexed by angular momentum, controlled by the Berry flux through the Fermi sea, with a Little-Parks-like periodicity in momentum space. We show that Berry curvature converts a nonchiral attractive interaction into a geometrically frustrated Cooper problem in momentum space. The relevant control parameter is the Berry-curvature flux enclosed by the Fermi sea, $Φ= b k_F^2$, which acts as an effective Aharonov-Bohm flux for the order parameter defined on the Fermi surface. As $Φ$ is tuned, the leading pairing instability switches between odd angular-momentum channels $m=1,3,5...$, producing a cascade of first-order transitions and Little-Parks-like oscillations of $T_c$.
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