Light-Induced Giant Rashba Spin–Orbit Coupling at Superconducting KTaO3(110) Heterointerfaces

Abstract

The 2D electron system (2DES) at the KTaO3 surface or heterointerface with 5d orbitals hosts extraordinary physical properties, including a stronger Rashba spin–orbit coupling (RSOC), higher superconducting transition temperature, and potential of topological superconductivity. Herein, a huge enhancement of RSOC under light illumination achieved at a superconducting amorphous-Hf0.5Zr0.5O2/KTaO3(110) heterointerfaces is reported. The superconducting transition is observed with Tc = 0.62 K and the 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 the 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.