Quantum transport signature of strain-induced scalar and pseudovector potentials in a crenelated h-BN/graphene heterostructure

Abstract

The sharp Dirac cone of electronic dispersion confers to graphene a remarkable sensitivity to strain. It is usually encoded in scalar and pseudovector potentials, induced by the modification of hopping parameters, which have given rise to new phenomena at the nanoscale, such as giant pseudomagnetic fields and valley polarization. Here, we unveil the effect of these potentials on the quantum transport across a succession of strain-induced barriers. We use high-mobility $h$-$\mathrm{BN}$–encapsulated graphene, transferred over a large ($10\times 10\text{μ}{\mathrm{m}}^2$) crenelated $h$-$\mathrm{BN}$ substrate. We show the emergence of a broad resistance ancillary peak at positive energy that arises from Klein-tunneling barriers induced by the tensile strain at the trench edges. Our theoretical study, in agreement with experiment, quantitatively highlights the balanced contributions of strain-induced scalar and pseudovector potentials on ballistic transport. Our results establish crenelated van der Waals heterostructures as a promising platform for strain engineering in view of applications and basic physics.