Dynamic band structure tuning of graphene moir\'e superlattices with pressure

摘要

Heterostructures of atomically-thin materials have attracted significantinterest owing to their ability to host novel electronic propertiesfundamentally distinct from their constituent layers. In the case of grapheneon boron nitride, the closely-matched lattices yield a moir\'e superlatticethat modifies the graphene electron dispersion and opens gaps both at theprimary Dirac point (DP) and the moir\'e-induced secondary Dirac point (SDP) inthe valence band. While significant effort has focused on controlling thesuperlattice period via the rotational stacking order, the role played by themagnitude of the interlayer coupling has received comparatively littleattention. Here, we modify the interaction between graphene and boron nitrideby tuning their separation with hydrostatic pressure. We observe a dramaticenhancement of the DP gap with increasing pressure, but little change in theSDP gap. Our surprising results identify the critical role played byatomic-scale structural deformations of the graphene lattice and reveal newopportunities for band structure engineering in van der Waals heterostructures.