Manipulation of valley isospins in strained graphene for valleytronics

Abstract

Graphene’s outstanding mechanical properties lend to strain engineering, allowing for future valley- tronics and nanoelectromechanic applications. In this work, we have found that a Gaussian-shaped strain on a graphene pen junction results in quantum Hall conductance oscillations due to the rotated angle between valley isospins at the graphene armchair edges. Furthermore, additional Fano resonances were observed as the value of the strain-induced pseudo-magnetic field approaches that of the external magnetic field. The lifted valley degeneracy, stemming from the interplay between the real and pseudo- magnetic fields, results in clearly valley-resolved Fano resonances. Exploring strain engineering as a means to control conductance through valley isospin manipulation is believed to open the door to po- tential graphene valleytronic devices. © 2019 Elsevier Ltd. All rights reserved.