Two-dimensional transition metal dichalcogenides with a hexagonal lattice : Room-temperature quantum spin Hall insulators

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Yandong Ma
  • Liangzhi Kou
  • Xiao Li
  • Ying Dai
  • Thomas Heine

Detail(s)

Original languageEnglish
Article number035442
Journal / PublicationPhysical Review B
Volume93
Issue number3
Publication statusPublished - 22 Jan 2016
Externally publishedYes

Abstract

So far, several transition metal dichalcogenide (TMDC)-based two-dimensional (2D) topological insulators (TIs) have been discovered, all of them based on a tetragonal lattice. However, in 2D crystals, the hexagonal rather than the tetragonal symmetry is the most common motif. Here, based on first principles calculations, we propose a class of stable 2D TMDCs of composition MX2(= Mo, W; X = S, Se, Te) with a hexagonal lattice. They are all in the same stability range as other 2D TMDC allotropes that have been demonstrated experimentally, and they are identified to be practical 2D TIs with large band gaps ranging from 41 to 198 meV, making them suitable for applications at room temperature. Besides, in contrast to tetragonal 2D TMDCs, their hexagonal lattice will greatly facilitate the integration of theses novel TI state van der Waals crystals with other hexagonal or honeycomb materials and thus provide a route for 2D material-based devices for wider nanoelectronic and spintronic applications. The nontrivial band gaps of both WSe2 and WTe2 2D crystals are 198 meV, which are larger than that in any previously reported TMDC-based TIs. These large band gaps entirely stem from the strong spin orbit coupling strength within the d orbitals of Mo/W atoms near the Fermi level. Our findings broaden the scientific and technological impact of both 2D TIs and TMDCs. ©2016 American Physical Society

Citation Format(s)

Two-dimensional transition metal dichalcogenides with a hexagonal lattice : Room-temperature quantum spin Hall insulators. / Ma, Yandong; Kou, Liangzhi; Li, Xiao; Dai, Ying; Heine, Thomas.

In: Physical Review B, Vol. 93, No. 3, 035442, 22.01.2016.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review