Probing Pseudospin-mixing Potential in Graphene/Boron Nitride Moire Superlattice by Infrared Spectroscopy

Graphene/boron nitride (BN) Moire superlattice, where the slow superlattice period is superimposed on a fast B-N oscillation, provides an attractive approach to engineer the electron pseudospin in graphene that goes beyond an electrostatic. Here we perform micro-infrared spectroscopy on graphene/BN superlattice, and find that the BN substrate effect in the context of pseudo-spin is much richer than an electrostatic potential. We further show that the BN substrate effect can be modified through electrostatic gating.