Thermal creep induced by cooling a superconducting vortex lattice

A perturbed system relaxes towards an equilibrium given by a minimum in the potential-energy landscape. This often occurs by thermally activated jumps over metastable states. The corresponding dynamics is called creep and follows Arrhenius' law. Here we consider the situation where the equilibrium position itself depends on temperature. We show that this effect occurs in the vortex lattice of the anisotropic superconductor 2H-NbSe2 when the magnetic field is tilted away from the principal axes, and that it leads to the peculiar appearance of creep when cooling the sample. Temperature determines the system's equilibrium state and at the same time brings the system back to equilibrium, playing a dual and antagonistic role. We expect that cooling-induced creep occurs in correlated systems with many degrees of freedom, allowing one to tune the equilibrium state via heat treatment.