Spin-dependent electron transfer through a ring-wire coupled junction: Role of in-plane electric field

Abstract We study spin-dependent transport in a hybrid magnetic system, where a non-magnetic (NM) wire is coupled to a side-attached antiferromagnetic (AFM) mesoscopic ring, placed between two non-magnetic electrodes subject to an in-plane electric field oriented perpendicular to the NM wire. The system is described within a tight-binding (TB) framework, and transport properties are computed using the non-equilibrium Green's function (NEGF) formalism. We consider two junction configurations distinguished by the ring-wire coupling: a single-coupled junction and a double-coupled junction. In the single-coupled configuration, the coupling geometry alone breaks the spin symmetry, yielding a finite spin polarization (SP) even without any external field. The in-plane electric field further enhances the symmetry breaking in both configurations, serving as an efficient tuning parameter that drives the SP nearly $100\%$ in the low-bias region. In the double-coupled configuration, spin symmetry is preserved in the absence of the external field, and the electric field acts as a sole source of symmetry breaking, producing a large SP. Finite temperature effects and different system sizes are examined, confirming the robustness of the observed features. To validate the findings over a wide parameter space, we considered different sets of parameters and found that the key signatures remain unchanged. Our results demonstrate that such hybrid structures are promising candidates for realizing an externally controllable spintronic device in low-dimensional systems.