Theory of vortex pinning in 2D superconductors by quantum fluctuations

Understanding the mechanism of vortex pinning has long been a challenge in elucidating the critical behaviors and enabling practical applications of superconductivity. However, the widely used Ginzburg-Landau theories, which are valid near the critical point, fail to account for recent experimental advancements at low-temperature limits or far from the critical point. Here, starting from a purely microscopic kinetic model, we develop a self-consistent thermodynamic theory of vortex dynamics that incorporates quantum superconducting phase fluctuations induced by disorder. Based on this theory, our numerical simulations yield the complete phase diagram of superconducting, vortex, and normal states in the presence of a magnetic field at finite temperatures. The inhomogeneous quantum phase fluctuations that arise with increasing disorder lead to a mixed state of superconducting (pairing) and normal-state (unpairing) islands, whereas the latter providing vortex pinning centers. Our theory suggests that increasing the carrier density can suppress vortex pinning and potentially explains the recently observed "vortex death" in intrinsically disordered 2D superconductors in the case of low carrier density.