Persistent current in a one-dimensional correlated disordered ring

We have investigated the persistent current in a one-dimensional (1D) correlated disordered ring. Chen et al. (Phys. Rev. B 61 (2000) 2008) studied the charge stiffness of the persistent current in a 1D correlated disordered ring and indicated that at a certain electron filling, the charge stiffness would be comparable to that in a clean ring. However, in the correlated disordered system, there is the possibility that the current is considerably enhanced by disorder correlation, irrespective of electron filling, because it gives rise to relaxation of the electron localization. In this article, in order to quantitatively examine the effect of disorder correlation on the current, we have calculated the current as a function of the correlation length. We then emphasize the significance of the disorder correlation length on the current against the viewpoint of Chen et al., since we have observed that as the correlation length approaches to the Fermi wavelength, negligibly small current in the region of the correlation length smaller than the Fermi wavelength recovers to the order of that in a clean ring. We have also found that an increase in the correlation length enlarges the current in the strongly localized regime much more than it enhances the current in the weakly localized regime. This suggests that the current in disordered potentials with large amplitude is easily influenced by disorder correlation compared to that in disordered potentials with small amplitude. Furthermore, computing the conductance in the same system, we have obtained similar feature to that of the current.