Using a combination of vertical transport measurements across and lateral
transport measurements along the LaAlO3β/SrTiO3β heterointerface, we
demonstrate that significant potential barrier lowering and band bending are
the cause of interfacial metallicity. Barrier lowering and enhanced band
bending extends over 2.5 nm into LaAlO3β as well as SrTiO3β. We explain
origins of high-temperature carrier saturation, lower carrier concentration,
and higher mobility in the sample with the thinnest LaAlO3β film on a
SrTiO3β substrate. Lateral transport results suggest that parasitic
interface scattering centers limit the low-temperature lateral electron
mobility of the metallic channel.Comment: 10 pages, 3 figures, and 1 tabl