The Effects Of Impurity Scattering In Two-Dimensional D-Density-Wave State

The d-density-wave (DDW) state is characterized by a condensate of electron-hole pairs. In such a state, the DDW order breaks parity and time-reversal symmetry as well as the translation invariance by one lattice constant and rotation byπ2. It was recently suggested that the typical characteristics of the psudogap of high-Tc cuprates can be explained by the DDW order model. Although the debate about the mechanism for the psudogap is far from settled, theoretical investigations for the features of the two-dimensional (2D) DDW state are interesting and important, and are likely to be helpful in understanding the superconducting mechanism and normal-state features of high-Tc cuprates. The effects of impurity scattering have been studied in the d-wave-superconducting (DWS) state for many years. Recently, the effects of impurity scattering in the DDW state have been received much attention by several groups. However, some results are in disagreement, and the weak-localization effect has not been yet investigated.In this paper, within the self-consistent T-matrix approximation, the methods of Green's function and diagrammatic techniques in quantum statistics are used to study the effects of nonmagnetic impurity scattering in 2D DDW state. We calculate the dc conductivity, and investigate the weak-localization effect. Our new results are as follows: (1) the rules are obtained for the effects of nonmagnetic impurity scattering in the DDW state. It is found that these rules are quite different from those of DWS and normal states due to the existence of DDW order. It is believed that these rules can be used to study the effects of nonmagnetic impurity scattering on equilibrium and transport properties in DDW state, such as conductivity, magnetoresistance, Hall effect et al..(2) We show that the time-reversal symmetry breaking leads to the disappearance of diffusive poles, and thus the usual weak-localization effect is absent in the DDW state. Such a result is qualitatively different from that for DWS state, in which the weak-localization effect has been shown to be prominent.The aim of this work is to predict theoretically the difference in effects of impurityscattering between the DDW and DWS states. The comparison between our predictions and the resulting experimental results might be helpful for the investigating of the mechanism for psudogap in high-Tc cuprates.