Thermodynamics of two-dimensional spin models with bimodal random-bond disorder

We use numerical linked cluster expansions to study the thermodynamic properties of the two-dimensional classical Ising, quantum XY, and quantum Heisenberg models with bimodal random-bond disorder on the square and honeycomb lattice. In all cases, the nearest-neighbor coupling between the spins takes values ±J with equal probability. We obtain the disorder-averaged (over all disorder configurations) energy, entropy, specific heat, and uniform magnetic susceptibility in each case. These results are compared with the corresponding ones in the clean models. Analytic expressions are obtained for low orders in the expansion of these thermodynamic quantities in inverse temperature.