Joseph, NB and Narayan, A (2021) Topological properties of bulk and bilayer 2M WS2: A first-principles study. In: Journal of Physics Condensed Matter, 33 (46).
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Abstract
Recently discovered 2M phase of bulk WS2 was observed to exhibit superconductivity with a critical temperature of 8.8 K, the highest reported among superconducting transition metal dichalcogenides. Also predicted to support protected surface states, it could be a potential topological superconductor. In the present study, we perform a detailed first-principles analysis of bulk and bilayer 2M WS2. We report a comprehensive investigation of the bulk phase, comparing structural and electronic properties obtained from different exchange correlation functionals to the experimentally reported values. By calculation of the Z 2 invariant and surface states, we give support for its non-trivial band nature. Based on the insights gained from the analysis of the bulk phase, we predict bilayer 2M WS2 as a new two-dimensional topological material. We demonstrate its dynamical stability from first-principles phonon computations and present its electronic properties, highlighting the band inversions between the W d and S p states. By means of Z 2 invariant computations and a calculation of the edge states, we show that bilayer 2M WS2 exhibits protected, robust edge states. The broken inversion symmetry in this newly proposed bilayer also leads to the presence of Berry curvature dipole and resulting non-linear responses. We compute the Berry curvature distribution and the dipole as a function of Fermi energy. We propose that Berry curvature dipole signals, which are absent in the centrosymmetric bulk 2M WS2, can be signatures of the bilayer. We hope our predictions lead to the experimental realization of this as-yet-undiscovered two-dimensional topological material. © 2021 IOP Publishing Ltd.
| Item Type: | Journal Article |
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| Publication: | Journal of Physics Condensed Matter |
| Publisher: | IOP Publishing Ltd |
| Additional Information: | The copyright for this article belongs to Authors |
| Keywords: | Calculations; Electronic document exchange; Electronic properties; Fruits; Stability; Surface states; Topology; Transition metals, Critical temperatures; Curvature distributions; Exchange-correlation functionals; Experimental realizations; First-principles study; Structural and electronic properties; Superconducting transitions; Topological properties, Tungsten compounds |
| Department/Centre: | Division of Chemical Sciences > Solid State & Structural Chemistry Unit |
| Date Deposited: | 03 Dec 2021 08:36 |
| Last Modified: | 03 Dec 2021 08:36 |
| URI: | http://eprints.iisc.ac.in/id/eprint/70241 |
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