title: Universal spin-Hall conductance fluctuations in two dimensions.
abstract: We report a theoretical investigation on spin-Hall conductance fluctuation of disordered four-terminal devices in the presence of Rashba or/and Dresselhaus spin-orbital interactions in two dimensions. As a function of disorder, the spin-Hall conductance GsH shows ballistic, diffusive, and insulating transport regimes. For given spin-orbit interactions, a universal spin-Hall conductance fluctuation (USCF) is found in the diffusive regime. The value of the USCF depends on the spin-orbit coupling tso but is independent of other system parameters. It is also independent of whether Rashba or Dresselhaus or both spin-orbital interactions are present. When tso is comparable to the hopping energy t, the USCF is a universal number approximately 0.18e/4pi. The distribution of GsH crosses over from a Gaussian distribution in the metallic regime to a non-Gaussian distribution in the insulating regime as the disorder strength is increased.
authors.affiliation: Department of Physics, The University of Hong Kong, Hong Kong, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ren
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Qiao
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Sun
authors.forename: Hong
authors.initials: H
authors.lastname: Guo