Intralayer and interlayer electron–phonon interactions in twisted graphene heterostructures

Abstract

The understanding of interactions between electrons and phonons in atomically thin heterostructures is crucial for the engineering of novel two-dimensional devices. Electron–phonon (el–ph) interactions in layered materials can occur involving electrons in the same layer or in different layers. Here we report on the possibility of distinguishing intralayer and interlayer el–ph interactions in samples of twisted bilayer graphene and of probing the intralayer process in graphene/h-BN by using Raman spectroscopy. In the intralayer process, the el–ph scattering occurs in a single graphene layer and the other layer (graphene or h-BN) imposes a periodic potential that backscatters the excited electron, whereas for the interlayer process the el–ph scattering occurs between states in the Dirac cones of adjacent graphene layers. Our methodology of using Raman spectroscopy to probe different types of el–ph interactions can be extended to study any kind of graphene-based heterostructure.

Abstract

Electron–phonon interactions in van der Waals layered materials can occur either within the same layer (intralayer) or in different layers (interlayer). Here, the authors use multi-wavelength Raman spectroscopy to probe intra- and inter-layer electron–phonon interactions in twisted graphene heterostructures.