Valley-Polarized Transport in Graphene Induced by Asymmetric Strain and Ferromagnetic Modulation

In this work, we theoretically investigate the valley-dependent electron transport properties of graphene modulated by two strained regions and a single ferromagnetic stripe based on the Dirac equation and the transfer-matrix method. By constructing a multi-region model, the conductances of the K and K’ valleys as well as the corresponding valley polarization are systematically calculated. The effects of the magnetic vector-potential, the strain-induced gauge potentials, the widths of the strained regions, and the competition parameter λ on the valley-resolved transport behavior are analyzed in detail. The results show that both the conductance and the valley polarization are highly sensitive to the external modulation parameters and the geometric structural parameters. By properly tuning the relative strength and spatial distribution of the magnetic vector-potential and strain, an effective control of valley polarization can be achieved. This work deepens the understanding of valley-dependent transport mechanisms in graphene and provides theoretical guidance for tunable valley filtering in graphene-based systems.