Nonequilibrium Peierls Transition

The nonequilibrium phase transition of an open Takayama-Lin Liu-Maki chain coupled with two reservoirs is investigated by combining a mean-field approximation and a formula characterizing nonequilibrium steady states, which is obtained from the algebraic field theoretical approach to nonequilibrium statistical mechanics. When the bias voltage is chosen as a control parameter, the phase transition between ordered and normal phases is found to be of first or second order. The current-voltage characteristics are S-shaped in some parameter region. In contrast, when the current is chosen as a control parameter, all the nontrivial solutions of the self-consistent equation are found to be stable. In this case, the phase transition between the ordered and normal phases is always of second order, and negative differential conductivity appears at low temperature.