Quantum Electrical Transport in Mesoscopic LaAlO3/SrTiO3 Heterostructures

Abstract

We report the fabrication and electrical measurements for LaAlO3/SrTiO3 (LAO/STO) heterostructures having various lateral sizes. When the sample size is reduced to the sub-micrometer range, the magnetoconductance (MC) curve deviates from classical parabolic behavior. Instead, a negative MC behavior appears with superimposed conductance fluctuations, which is attributed to weak antilocalization and universal conductance fluctuations. Using the Maekawa-Fukuyama model, the spin-orbit scattering and phase coherence lengths are estimated from the MC data, which are dependent on the gate voltage and temperature. Our comprehensive study shows that LAO/STO heterointerfaces provide a useful platform to explore quantum coherent transport of strongly correlated electrons. (C) 2013 The Japan Society of Applied Physics