Effect of a homogeneous magnetic field on one-dimensional antiferromagnetic superconductors

Applying the mean-field theory, we investigate the effect of an external homogeneous magnetic field \({\vec H_O}\), and the staggered magnetic field \({\vec H_Q}\), arising from antiferromagnetism on superconductors with one-dimensional incommensurate bands. The superconducting order parameter is spatially homogeneous (BCS state) for the weak Ho and oscillates in space (FF state) for the strong Ho. The superconducting domains on HQ−Ho plane as temperature decreases is shown by calculating the ground state and the second-order phase transition temperature. It is found that the interplay between \({\vec H_O}\) and \({\vec H_Q}\) leads to the crucial differences between the domain of \({\vec H_O}\)//\({\vec H_Q}\) and that of \({\vec H_O} \bot {\vec H_Q}\). Further, the effect of the one-dimensional fluctuation is examined by use of the bosonization method.