DEFECT ENERGY WITH CONJUGATE BOUNDARY-CONDITIONS IN SPIN-GLASS MODELSIN 2 DIMENSIONS

We calculate the naive defect energy Delta E of Ising spin glass (SG) models in two dimensions using conjugate boundary conditions. We predi ct that, in the +/-J model, the averaged value <(Delta E)over bar> con verges to some nonzero value in the thermodynamic limit in contrast wi th <(Delta E)over bar>=0 in the Gaussian model. This prediction suppor ts a recent Monte Carlo prediction of the presence of the SG phase at finite temperatures in the +/-J Ising model. We also calculate the int erface free energy to confirm it. [S0163-1829(98)50842-9].