Session 1D - Symposium on “Twistronics”

Manish Jain

Graphene on hBN: bands with a twist

The relationship between energy (E) and wave vector (k, the inverse of wavelength) is a key characteristic of quantum systems. In metals, the energy of electrons varies quadratically with k, whereas for photons, the relationship between E and k is linear. This means that electrons in metals are non-relativistic, while photons adhere to Einstein's theory of relativity. Graphene presents a condensed matter system that allows the study of relativistic effects in a laboratory setting. In this talk, how the dispersion relation in bilayer graphene can be transformed from non-relativistic to relativistic by creating Moiré superlattices will be explained. This is done by placing graphene on an insulator, boron nitride (hBN), which has a slight lattice mismatch with graphene. The effect is further enhanced by introducing a small twist between the graphene and the hBN lattice. How this alteration in the electronic dispersion relation of graphene influences its electronic properties will be discussed.