Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 74: Frontiers of electronic structure theory: 2D TMDC and excitonic effects
HL 74.5: Talk
Thursday, March 19, 2015, 11:45–12:00, MA 004
Origin of metallic edge states in transition-metal-dichalcogenide nanostructures — •Marco Gibertini and Nicola Marzari — Theory and Simulation of Materials (THEOS) and National Center for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, Switzerland
The existence of metallic edge states in transition-metal-dichalcogenide nanostructures has been reported both in the experimental and theoretical literature. Such nanostructures include for instance triangular islands and zigzag nanoribbons. Nonetheless, a thorough understanding of the mechanism giving rise to metallic states at the edge of such bulk insulating materials is still missing. Here we suggest a possible origin of such states and support our findings with first-principles density-functional-theory simulations. The key observation is that transition metal dichalcogenides like MoS2 display a finite formal polarization that induces a charge reconstruction with the appearance of free carriers at the edges. We also suggest possible innovative applications in nanoelectronics and solar-energy devices.