Light‐Induced Giant Rashba Spin–Orbit Coupling at Superconducting KTaO ₃(110) Heterointerfaces

Abstract

The 2D electron system (2DES) at the KTaO ₃ 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‐Hf _0.5Zr _0.5O ₂/KTaO ₃(110) heterointerfaces is reported. The superconducting transition is observed with T _c = 0.62 K and the temperature‐dependent upper critical field reveals the interaction between spin–orbit scattering and superconductivity. A strong RSOC with B _so = 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 B _so = 12.6 T achieved near the Lifshitz transition point n _c ≈ 4.1 × 10 ¹³ cm ⁻². The highly tunable giant RSOC at KTaO ₃(110)‐based superconducting interfaces show great potential for spintronics.