  Magnetotransport measurements of charge carriers at the interface of a
LaAlO3/SrTiO3 heterostructure with 26 unit cells of LaAlO3 show Hall resistance
and magnetoresistance which at low and high temperatures is described by a
single channel of electron-like charge carriers. At intermediate temperatures,
we observe non-linear Hall resistance and positive magnetoresistance,
establishing the presence of at least two electron-like channels with
significantly different mobilities and carrier concentrations. These channels
are separated by 6 meV in energy and their temperature dependent occupation and
mobilities are responsible for the observed transport properties of the
interface. We observe that one of the channels has a mobility that decreases
with decreasing temperature, consistent with magnetic scattering in this
channel.
