Quantum Electrical Transport in Mesoscopic LaAlO₃/SrTiO₃Heterostructures

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.