Abstract: The interplay between chiral tunneling and spin-momentum locking of helical surface states leads to spin amplification and filtering in a 3D Topological Insulator (TI). Chiral tunneling across a TI pn junction allows normally incident electrons to transmit, while the rest are reflected with their spins flipped due to spin-momentum locking. The net result is that the spin current is enhanced while the dissipative charge current is simultaneously suppressed, leading to an extremely large, tunable longitudinal spin Hall angle (˜20) at the reflected end. At the transmitted end, the angle stays close to one and the electrons are completely spin polarized.

Abstract: An electronic device can include a dielectric layer, and a graphene layer including a first surface located upon the dielectric layer. The electronic device can include a first electrode, a second electrode, and a third electrode each located upon the dielectric layer on a surface opposite the graphene layer. The first and second electrodes can be spaced apart along a longitudinal axis of the electronic device to define a first gap between the first and second electrodes, and the second and third electrodes are spaced apart along the longitudinal axis of the electronic device to define a second gap between the second and third electrodes. At least one of the first gap or the second gap can be angled so as to be neither parallel nor perpendicular to the longitudinal axis of the electronic device.

Abstract: The interplay between chiral tunneling and spin-momentum locking of helical surface states leads to spin amplification and filtering in a 3D Topological Insulator (TI). Chiral tunneling across a TI pn junction allows normally incident electrons to transmit, while the rest are reflected with their spins flipped due to spin-momentum locking. The net result is that the spin current is enhanced while the dissipative charge current is simultaneously suppressed, leading to an extremely large, tunable longitudinal spin Hall angle (˜20) at the reflected end. At the transmitted end, the angle stays close to one and the electrons are completely spin polarized.

Abstract: An electronic device can include a dielectric layer, and a graphene layer including a first surface located upon the dielectric layer. The electronic device can include a first electrode, a second electrode, and a third electrode each located upon the dielectric layer on a surface opposite the graphene layer. The first and second electrodes can be spaced apart along a longitudinal axis of the electronic device to define a first gap between the first and second electrodes, and the second and third electrodes are spaced apart along the longitudinal axis of the electronic device to define a second gap between the second and third electrodes. At least one of the first gap or the second gap can be angled so as to be neither parallel nor perpendicular to the longitudinal axis of the electronic device.