2025/09/23 by Anton Talkachov, Egor Babaev, Talkachov, Anton +1
Physics and Astronomy · #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #Superconductivity (cond-mat.supr-con) #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2509.19137
openalex publication_date 2025/09/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study conditions of the appearance of U(1)× ℤ2 superconducting states that spontaneously break time-reversal symmetry (BTRS) on a square lattice as a function of applied stress. Calculations show that if critical temperatures coincide at zero stress, they exhibit a linear kink and no kink otherwise for uniaxial and isotropic strain. Linear kink is absent for shear strain. We find that in general, the microscopic calculations show a complex phase diagram, for example, non-monotonic behavior of BTRS transition. Another beyond-Ginzburg-Landau theory result is that U(1) critical temperature can decrease under compressional [100] uniaxial strain for small Poisson ratio materials. In the second part of the paper, we consider the effects of boundaries and finiteness of the sample on the strain-induced splitting of TcU(1) and Tcℤ2 transitions. A finite sample has BTRS boundary states with persistent superconducting currents over a wide range of band filling. Overall, the BTRS dome occupies a larger band filling--temperature phase space region for a mesoscopic sample with [110] surface compared to an infinite system. Hence, the presence of boundaries helps to stabilize the BTRS phase.