Strain-induced pseudo gauge potential based graphene valley beam splitter

Valley polarization is paramount for leveraging the valley degree of freedom in encoding and computing information. Using scattering theory based quantum transport calculations, his work proposes a graphene-based multi-terminal valley beam splitter for separating valley polarized beams in real space. Our proposed approach leverages the effect of strain combined with the negative refraction property in graphene. The uniaxial smooth strain applied along a transverse axis to the transport direction induces the pseudo gauge potential, which acts differently on K and K’ transverse wavevector components and directs their trajectories in opposite directions along the longitudinal axis. Graphene acts as a meta-surface with negative refraction properties for PN junction. Thus, the angular transmission spectra of each valley are configured to design robust polarization for the finite energy range by modulating strain and doping electrostatically.

Reference:

1. Fujita, T., et. al. Applied Physics Letters 97, no. 4 (2010): 043508

2. McRae, A. C. et.al. Physical Review Applied 11, no. 5 (2019): 054019.