Engineering spin polarization in a driven multistranded magnetic quantum network

Abstract

Possible engineering of spin polarization through a multistranded magnetic quantum network in the presence of light irradiation is reported. Each site of the network is associated with a net magnetic moment which provides a spin-dependent scattering via spin-spin exchange interaction, yielding a finite spin polarization across the network. The quantum system is described within a tight-binding framework where the irradiation effect is incorporated through Floquet-Bloch prescription. The spin-polarization coefficient, measured by determining spin-dependent transmission probabilities following the Green's function formalism, shows several atypical features with irradiation parameters. Apart from getting a high degree of spin polarization, a complete phase reversal can be achieved. These two issues are extremely important in designing efficient spin-based electronic devices. A detailed mathematical description is given to decouple the Hamiltonian of a generalized multistranded magnetic ladder into distinct one-dimensional lattices in separate spin subspaces for any arbitrary orientation of local spin, which clearly illustrates the allowed energy spin subbands. Effects of system size and uncorrelated disorder on spin polarization are critically examined. Finally, we discuss the possible experimental realization of our magnetic quantum systemto regulate the degree and phase of spin polarization by irradiating a magnetic sample, and thus we believe that the present analysis may provide a route of engineering spin-dependent electron transfer through a spin-polarized device.