Gate-voltage control of anisotropic bilinear magnetoresistance at Rashba interfaces

Bilinear magnetoresistance (BMR), exhibiting a linear response to magnetic field or applied current, has garnered significant attention in recent research. While most previous works have focused on isotropic BMR, arising from isotropic band structure or the spin Hall effect, we report on a strongly anisotropic BMR (ABMR) observed at the KTaO₃ Rashba interface, characterized by a unique low-symmetry Fermi surface. For the first time, we have successfully achieved significant regulation of ABMR through the application of gate voltage. Our quantified analysis reveals a profound link between the tunable anisotropy in Rashba spin splitting and the precise modulation of the Fermi level filling, highlighting its central role in governing gate-modulated ABMR. Additionally, we introduce a rigorous physical model that provides a deep and nuanced understanding of the mechanisms underlying gate-voltage-controlled ABMR. This control over electronic processes in low-dimensional systems holds immense potential for both fundamental physics research and the development of advanced multi-channel spintronic devices.