Garaud Julien, Babaev Egor
Institut Denis Poisson CNRS-UMR 7013, Université de Tours, 37200 Tours, France.
Nordita, Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden.
Phys Rev Lett. 2022 Aug 19;129(8):087602. doi: 10.1103/PhysRevLett.129.087602.
Recent experiments [Grinenko et al. Nat. Phys. 17, 1254 (2021)NPAHAX1745-247310.1038/s41567-021-01350-9] reported the observation of a condensate of four-fermion composites. This is a resistive state that spontaneously breaks the time-reversal symmetry, leading to unconventional magnetic properties, detected in muon spin rotation experiments and by the appearance of a spontaneous Nernst effect. In this Letter, we derive an effective model for the four-fermion order parameter that describes the observed spontaneous magnetic fields in this state. We show that this model, which is alike to the Faddeev-Skyrme model can host skyrmions: magnetic-flux-carrying topological excitations.
近期的实验[格林年科等人，《自然·物理学》17, 1254 (2021)；NPAHAX1745 - 2473；10.1038/s41567 - 021 - 01350 - 9]报道了对四费米子复合体凝聚态的观测。这是一种电阻态，它自发地打破了时间反演对称性，导致了非常规的磁性特性，这在μ子自旋旋转实验以及通过自发能斯特效应的出现得以检测。在本信函中，我们推导了一个用于四费米子序参量的有效模型，该模型描述了此状态下观测到的自发磁场。我们表明，这个类似于法捷耶夫 - 斯凯尔姆模型的模型能够容纳斯格明子：携带磁通量的拓扑激发。
