Time and place: 2019.4.24, 15:30 pm, Wuhan National High Magnetic Field Center B206

Presenter: Walter Escoffier

Title: Aperiodic quantum oscillations in the two-dimensional electron gas at the LaAlO₃/SrTiO₃ interface

Abstract:

We investigate the transport properties of a high-mobility quasi-two-dimensional electron gas at the interface between two insulators LaAlO₃ and SrTiO₃. Since its first discovery in 2004, the electronic band structure derived from magnetotransport studies in different experimental conditions of temperature and magnetic field provided equivocal conclusions. Recently, the use of high magnetic field clearly revealed non 1/B-periodic magneto-resistance oscillations, as evidenced by a highly non-linear Landau plot (Landau level index versus 1/B). Among various scenarios, the Roth-Gao-Niu model provides a natural explanation for this effect, in relation with the magnetic response functions of the system. The experimental magneto-transport results are discussed jointly with dedicated theoretical DFT band-structure calculations, as well as with structural analysis of the interface using high-resolution scanning transmission electron microscopy.