Abstract
We investigate numerically the quasiparticle density of states for a two-dimensional, disordered superconductor in which both time-reversal and spin-rotation symmetries are broken. As a generic single-particle description of this class of systems (symmetry class D), we use the Cho-Fisher version of the network model. This has three phases: a thermal insulator, a thermal metal, and a quantized thermal Hall conductor. In the thermal metal, we find a logarithmic divergence in as , as predicted from sigma model calculations. Finite-size effects lead to superimposed oscillations, as expected from random-matrix theory. In the thermal insulator and quantized thermal Hall conductor, we find that is finite at . At the plateau transition between these phases, decreases toward zero as is reduced, in line with the result derived from calculations for Dirac fermions with random mass.
1 More- Received 25 October 2006
DOI:https://doi.org/10.1103/PhysRevB.75.245321
©2007 American Physical Society