Two-dimensional Coulomb glass as a model for vortex pinning in superconducting films
Abstract
A glass model of vortex pinning in highly disordered thin superconducting films in magnetic fields B Hc2 at low temperatures is proposed. Strong collective pinning of a vortex system realized in disordered superconductors that are close to the quantum phase transition to the insulating phase -- such as In Ox, Nb N, Ti N, Mo Ge, nano-granular aluminium, and others -- is considered theoretically for the first time. Utilizing the replica trick developed for the spin glass theory, we demonstrate that such vortex system is in non-ergodic state of glass type with large kinetic inductance per square LK. Distribution function of local pinning energies is calculated, and it is shown that it possesses a wide gap, i.e. the probability to find a weakly pinned vortex is extremely low.