Conductance of disordered wires with symplectic symmetry: Comparison between odd- and even-channel cases

The conductance of disordered wires with symplectic symmetry is studied by numerical simulations on the basis of a tight-binding model on a square lattice consisting of M lattice sites in the transverse direction. If the potential range of scatterers is much larger than the lattice constant, the number N of conducting channels becomes odd (even) when M is odd (even). The average dimensionless conductance (g) is calculated as a function of system length L. It is shown that when N is odd, the conductance behaves as (g) --> 1 with increasing L. This indicates the absence of Anderson localization. In the even-channel case, the ordinary localization behavior arises and (g) decays exponentially with increasing L. It is also shown that the decay of (g) is much faster in the odd-channel case than in the even-channel case. These numerical results are in qualitative agreement with existing analytic theories.