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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 30: SrTiO₃: A Versatile Material from Bulk Quantum Paraelectric to 2D Superconductor III (joint session TT/KFM/MA/O)

KFM 30.10: Talk

Friday, March 22, 2024, 12:00–12:15, H 0104

Enhanced Non-linear Response by Manipulating the Dirac Point in the (111) LaTiO₃/SrTiO₃ Interface — •Yoram Dagan, Gal Tuvia, Amir Burshtein, Itai Silber, Amnon Aharony, Ora Entin-Wohlman, and Moshe Goldstein — School of Physics and Astronomy, Tel Aviv University

Tunable spin-orbit interaction (SOI) is an important feature for future spin-based devices. In the presence of a magnetic field, SOI induces an asymmetry in the energy bands, which can produce non-linear transport effects (V∼ I²). Here, we focus on such effects to study the role of SOI in the (111) LaTiO₃/SrTiO₃ interface. This system is a convenient platform for understanding the role of SOI since it exhibits a single-band Hall-response through the entire gate-voltage range studied. We report a pronounced rise in the non-linear longitudinal resistance at a critical in-plane field H_cr. This rise disappears when a small out-of-plane field component is present. We explain these results by considering the location of the Dirac point formed at the crossing of the spin-split energy bands. An in-plane magnetic field pushes this point outside of the Fermi contour, and consequently changes the symmetry of the Fermi contours and intensifies the non-linear transport. An out-of-plane magnetic field opens a gap at the Dirac point, thereby significantly diminishing the non-linear effects. We propose that magnetoresistance effects previously reported in SrTiO₃-based interfaces could be comprehended within our suggested scenario.

Keywords: Nonlinear transport; Spin-orbit interaction; Superconductivity