Valley switch in a graphene superlattice due to pseudo-Andreev reflection

Abstract

Dirac electrons in graphene have a valley degree of freedom that is being explored as a carrier of information. In that context of "valleytronics" one seeks to coherently manipulate the valley index. Here we show that reflection from a superlattice potential can provide a valley switch: Electrons approaching a pristine-graphene--superlattice-graphene interface near normal incidence are reflected in the opposite valley. We identify the topological origin of this valley switch, by mapping the problem onto that of Andreev reflection from a topological superconductor, with the electron-hole degree of freedom playing the role of the valley index. The valley switch is ideal at a symmetry point of the superlattice potential, but remains close to 100% in a broad parameter range.

arXiv comment5 pages, 4 figures (published version, "Editor's suggestion")

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Cited by in corpus (9)

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• Valley-driven Zitterbewegung in Kekulé-distorted graphene
• Anomalous Cyclotron Motion in Graphene Superlattice Cavities
• Light-modulated Josephson effect in Kekulé patterned graphene
• Optoelectronic Fingerprints of Interference between Different Charge Carriers in Graphene Superlattices and Analogies to Twisted Graphene Bilayers
• Valley current filtering and reversal by parallel side contacted armchair nanotubes
• Origins of Valley Current Reversal in Partially Overlapped Graphene Layers
• Valley Gapless Semiconductor: Models and Applications
• Tunnel Valley Current Filter in the Partially Overlapped Graphene under the Vertical Electric Field