Electronic States at Lateral Interfaces in Transition Metal Dichalcogenides

Lateral heterostructures of two-dimensional crystals have received attention as defect free interfaces are increasingly grown in experiments. These interfaces show excitations unlike those at the original materials, suggesting the robustness of the interface. Tight binding and first principles calculations show that electronic states along the interface lie within the band gap of the bulk structure and provide a platform for possible use as high performance thermoelectric materials, spin-valley filters without the need for external gating, excitonic solar cells, and photocatalysis [1]. In this work, we explore the appearance of interfacial states in continuum models of such massive Dirac systems at low energy. We use k*p models to characterize lateral interfaces of various 2D materials and analyze the results of appropriate boundary conditions on various types of interfaces. This approach is able to describe midgap interface states that appear under mass or band inversion, as well as sign changes in effective curvature across the two materials. The states exhibit complex dispersion curves with strong spin-orbit effects, while being localized along the interface with different features in different materials.

[1] O. Avalos-Ovando et al., J. Phys. Cond. Matt. Vol 31, 21 (2019).