Impedance-based interfacial analysis of the LaAlO3/SrTiO3 oxide heterostructure involving a 2-dimensional electron gas layer

Abstract

The 2-dimensional electron gas (2DEG) at the LaAlO 3 /SrTiO 3 heterointerface was analyzed using frequency-dependent impedance spectroscopy. The electrical conduction of 2DEG significantly influences the high-frequency impedance and induces dielectric amplification at low frequency regimes. The impedance responses obtained from the LaAlO 3 /SrTiO 3 oxide was modeled using an equivalent circuit model. The frequency-dependent characterization used here does not necessitate the formation of ohmic contacts between the 2DEG layer and the adjacent electrodes. Through thermal bias-stress tests, the 2DEG conduction mechanism is proposed to partially originate from the oxygen vacancy-controlled defect concepts, indicating the controllability of 2DEG transport. • 2-dimensional electron gas (2DEG) is formed at LaAlO 3 /SrTiO 3 heterointerface. • Impedance spectroscopy was applied onto the 2DEG LaAlO 3 /SrTiO 3 system. • The 2DEG LaAlO 3 /SrTiO 3 system was modeled using an equivalent circuit model. • The origin of the 2EDG layer was interpreted in terms of oxygen vacancy defects.