EFFECT OF THE IMPURITY SCATTERING ON THE ZERO-TEMPERATURE PENETRATION DEPTH IN D(X2-Y2) SYMMETRY

We have calculated the effect of impurity scattering in the Born (weak) and unitary (strong) limits on the absolute value of the zero-temperature penetration depth lambda(0). The gap is taken to exhibit d(x2-y2) symmetry in the copper-oxygen planes and a model two-dimensional tight-binding band structure is used with nearest-neighbor hopping only. Impurities depress the value of the critical temperature and, at the same time, increase the value of lambda(0). Weak and strong scattering are compared. The predicted increase in lambda(0) is smaller than indicated in recent experiments.