FINITE-SIZE-SCALING BEHAVIOR OF THE TRACER SURFACE-DIFFUSION COEFFICIENT NEAR A 2ND-ORDER PHASE-TRANSITION

We investigate the finite-size scaling behavior of the tracer surface diffusion coefficient in the vicinity of a second-order phase transiti on. For this purpose, we use a lattice gas model of repulsively intera cting particles on a square lattice. For all lattice sizes L studied, the measured tracer surface diffusion coefficient, D-t, is a smooth fu nction, having an inflexion point at critical temperature. Its derivat ive, partial derivative D-t/partial derivative(1/k(B)T), exhibits cusp -like maximum which is a) sharply pronounced and b) converged to T-c(i nfinity) for large lattice sizes. We have analyzed the finite-size beh avior of Dt and obtained its critical exponent sigma(t) = 0.665 +/- 0. 003.