Light-induced giant Rashba spin-orbit coupling at superconducting KTaO3 (110) heterointerfaces.

Abstract

The two-dimensional electron system (2DES) at KTaO3 surface or heterointerface with 5d orbitals hosts extraordinary physical properties including the stronger Rashba spin-orbit coupling (RSOC), higher superconducting transition temperature, and potential of topological superconductivity. Herein, we report a huge enhancement of RSOC under light illumination achieved at a superconducting amorphous-Hf0.5 Zr0.5 O2 /KTaO3 (110) heterointerfaces. The superconducting transition is observed with Tc = 0.62 K and temperature dependent upper critical field reveals the interaction between spin-orbit scattering and superconductivity. A strong RSOC with Bso =1.9 T is revealed by weak antilocalization in normal state, which undergoes sevenfold enhancement under light illumination. Furthermore, RSOC strength develops a dome-shaped dependence of carrier density with the maximum of Bso =12.6 T achieved near the Lifshitz transition point nc ∼ 4.1×1013 cm-2 . The highly tunable giant RSOC at KTaO3 (110)-based superconducting interfaces show great potential for spintronics. This article is protected by copyright. All rights reserved.