Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 74: Frontiers of electronic structure theory: 2D TMDC and excitonic effects

HL 74.5: Vortrag

Donnerstag, 19. März 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.