Size effects on transport properties in topological Anderson insulators

We study the size effects on the transport properties in topological Anderson insulators (TAIs) by means of the Landauer-Buttiker formalism combined with the nonequilibrium Green function method. Conductances calculated for serval different widths of the nanoribbons reveal that there is no longer quantized plateaus for narrow nanoribbons. The local spin-resolved current distribution demonstrates that the edge states on the two sides can be coupled, leading to enhancement of backscattering as the width of the nanoribbon decreases, thus destroying the perfect quantization phenomena in the TAI. We also show that the main contribution to the nonquantized conductance also comes from edge states. Experiment proposals on TAI are discussed finally.