Topological nature of in‐gap bound states in disordered large‐gap monolayer transition metal dichalcogenides. Issue 5 (8th April 2016)

• Record Type: Journal Article
• Authors: Qu, Fanyao; Villegas‐Lelovsky, L.; Diniz, G. S.
• Is Part Of: Physica status solidi. Volume 10:Issue 5(2016)
• Page Start: 409
• Page End: 414
• Publication Date: 2016-04-08
• Subjects: transition‐metal dichalcogenides -- MoS2 -- topological insulators -- in‐gap bound states -- monolayers; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201600029
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : We propose a physical model based on disordered (a hole punched inside a material) monolayer transition metal dichalcogenides (TMDs) to demonstrate a large‐gap quantum valley Hall insulator. We find an emergence of bound states lying inside the bulk gap of the TMDs. They are strongly affected by spin–valley coupling, rest‐ and kinetic‐mass terms and the hole size. In addition, in the whole range of the hole size, at least two in‐gap bound states with opposite angular momentum, circulating around the edge of the hole, exist.Their topological insulator (TI) feature is analyzed by the Chern number, characterized by spacial distribution of their probabilities and confirmed by energy dispersion curves (energy vs. angular momentum). It not only sheds light on overcoming low‐temperature operating limitation of existing narrow‐gap TIs, but also opens an opportunity to realize valley‐ and spin‐qubits. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) Abstract : The authors discuss the conditions for the in‐gap bound states (IGBS) formation in a hole‐punched transition metal dichalcogenide are discussed. By combining different regimes of hole border confinement, spin‐orbit coupling, and rest/kinetic mass, strong modifications are observed in the energy spectrum of the IGBS. Under appropriate conditions, at least two IGBS exist for various hole sizes. The topological nature of the IGBS manifests the probability distribution functions of time‐reversed states in different valleys.