4 research outputs found
A topological characterization of delocalization in a spin-orbit coupling system
We show that wavefunctions in a two-dimensional (2D) electron system with
spin-orbit coupling can be characterized by a topological quantity--the Chern
integer due to the existence of the intrinsic Kramers degeneracy. The
localization-delocalization transition in such a system is studied in terms of
such a Chern number description, which reproduces the known metal-insulator
transition point. The present work suggests a unified picture for various known
2D delocalization phenomena based on the same topological characterization.Comment: RevTex, 12 pages; Two PostScript figure
Classical advection of guiding centers in a random magnetic field
We investigate theoretically and experimentally classical advective
transport in a 2D electron gas in a random magnetic field.
For uniform external perpendicular magnetic fields large
compared to the random field we observe a strong enhancement
of conductance compared to the ordinary Drude value. This can be
understood as resulting from advection of cyclotron guiding centers. For low
disorder this enhancement shows non-trivial scaling as
a function of scattering time, with consistency between theory and
experiment