Relationship between Magnetic Anisotropy below Pseudogap Temperature and Short-Range Antiferromagnetic Order in High-Temperature Cuprate Superconductor

The central issue in high-temperatuie cuprate superconductors is the pseudogap state appearing below the pseudogap temperatuie T*, which is well above the superconducting tiansition temperatuie.In this study, we theoretically investigate the rapid increase of the magnetic anisotropy below the pseudogap temperature detected by the recent torquemagnetometry measurements on YBa2Cu3Oy [Y. Sato et al., Nat. Phys.13,1074 (2017)]. Applying the spin Green's function formalism including the Dzyaloshinskii-Moriya interaction arising from the buckling of the CuO2 plane, we obtain results that are in good agreement with the experiment and find a scaling relationship. Our analysis suggests that the characteristic temperature associated with the magnetic anisotropy, which coincides with T*,is not a phase transition temperature but a crossover temperature associated with the short-range antiferromagnetic older.