Long-Range Order in Electronic Transport through Disordered Metal Film
Ron Folman
Dept. of Physics, Ben Gurion University
Ultracold atom magnetic field microscopy enables the probing of
current flow patterns in planar structures with unprecedented
sensitivity. In polycrystalline metal (gold) films we observe
long-range correlations forming organized patterns oriented at
45 degrees relative to the mean current flow, even at room
temperature and at length scales orders of magnitude larger than
the diffusion length or the grain size. The preference to form
patterns at these angles is a direct consequence of universal
scattering properties at defects. The observed amplitude of the
current direction fluctuations scales inversely to that expected
from the relative thickness variations, the grain size and the
defect concentration, all determined independently by standard
methods. This indicates that ultracold atom magnetometry enables
new insight into the interplay between disorder and transport.
[1] Science 319, 1226 (2008)
[2] cond-mat 0803.4307