IMPURITY EFFECT ON THE 2-DIMENSIONAL SPIN-DENSITY-WAVE

We investigate here the effect of non-magnetic impurities on the SDW s tate of the two-dimensional electron gas at half filling. The dependen ce on the impurity concentration (n(i)) of the relevant SDW quantities is obtained within an Abrikosov-Gorkov-type approach. To account appr opriately for the actual Fermi surface topology we introduce a classif ication of the electron-impurity scattering processes. Analytic result s are obtained for a general type scattering in the limit of low- and high n(i)-values. In addition, the presently introduced classification allows us to find a (rather general) class of scattering processes fo r which analytic results can be derived for arbitrary n(i) values. The logarithmic singularity in the density of electronic states turns out to have a notable (qualitative and quantitative) influence on the SDW properties in the presence of impurities. The limitations of the pres ently employed approximations are also discussed.