Control of competing superconductivity and charge order by nonequilibrium currents

We study the competing charge-density-wave and superconducting order in the attractive Hubbard model under a voltage bias, using steady-state nonequilibrium dynamical mean-field theory. We show that the charge-density wave is suppressed in a current-carrying nonequilibrium steady state. This effect is beyond a simple Joule-heating mechanism and a "supercooled" metallic state is stabilized at a nonequilibrium temperature lower than the equilibrium superconducting T-c. On the other hand, a current-carrying superconducting state is dissipationless and thus not subject to the same nonthermal suppression, and can therefore nucleate out of the supercooled metal, e.g., in a resistive switching experiment. The fact that an electric current can change the relative stability of different phases compared to thermal equilibrium, even when a system appears locally thermal due to electron-electron scattering, provides a general perspective to control intertwined orders out of equilibrium.