Atomically thin sheets such as graphene and monolayer transition metal dichalcogenides hosts rich structural variety and desirable properties that derive from their 2D form, such as strong light-matter interaction and mechanical flexibility. My research employs accurate first-principles calculations to model their growth and characterization, in close collaboration with several experimental teams.
The calculation of resonance Raman intensities in 2D materials requires knowledge of the dielectric response including excitonic effects using many-body perturbation theory. We develop a computational framework for calculating Raman intensities from first-principles following a diagrammatic approach, which scales favorably with respect to the number of Raman modes compared to existing implementations using finite displacements.
2D Growth control
Increasingly successful efforts are being directed to the synthesis of millimeter-scale 2D monolayers with high sample qualities. These advances motivate the nanoscale control over 2D growth by properly designing the topographies and tailoring the surface chemistry of the substrate. We employ density functional theory and empirical forcefield calculations to predict grain boundary control and epitaxial control as applicable to a broad class of sheet-substrate combinations.