Berry-curvature-mediated valley-Hall and charge-Hall effects in graphene via strain engineering

Abstract

We point out a practical way to induce a finite charge-Hall conductivity in graphene via an off-diagonal strain. Our conclusions are based on a general analysis and supported by numerical examples. The interplay between a substrate-induced gap and the strain is discussed. We show that the substrate-induced gap itself does not break the symmetry that maps one valley onto the other, and hence does not yield a net charge-Hall effect. The net charge-Hall conductivity is found to be sizable and should be observable in the presence of both the gap and the strain. The sign of the Hall conductivity can be tuned by varying the strain parameters. The valley-Hall conductivity is studied as well. The valley and the orbital magnetic moment accumulations on the sample edges may be detected in a Hall conductivity experiment.