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Gap opening and lar...
Gap opening and large spin–orbit splitting in MX2 (M = Mo,W; X = S,Se,Te) from the interplay between crystal field and hybridisations : insights from ab-initio theory
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- Autieri, Carmine (författare)
- Uppsala universitet,Materialteori,.
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- Bouhon, Adrien (författare)
- Uppsala universitet,Materialteori
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- Sanyal, Biplab (författare)
- Uppsala universitet,Materialteori
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(creator_code:org_t)
- 2017-10-06
- 2017
- Engelska.
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Ingår i: Philosophical Magazine. - : Informa UK Limited. - 1478-6435 .- 1478-6443. ; 97:35, s. 3381-3395
- Relaterad länk:
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http://arxiv.org/pdf...
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visa fler...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- By means of first-principles density functional calculations, we study the maximally localised Wannier functions for the 2D transition metal dichalcogenides MX2 (M = Mo, W; X = S, Se, Te). We have found that part of the energy gap is opened by the crystal field splitting induced by the X-2-like atoms. The inversion of the band character between the Gamma and the K points of the Brillouin zone is due to the M-M hybridisation. The consequence of this inversion is the closure of the gap in absence of the M-X hybridisation. The M-X hybridisation is the only one that tends to open the gap at every k-point. It is found that the change in the M-X and M-M hybridisation is the main responsible for the difference in the gap between the different dichalcogenide materials. The inversion of the bands gives rise to different spinorbit splitting at Gamma and K point in the valence band. The different character of the gap at Gamma and K point offers the chance to manipulate the semiconducting properties of these compounds. For a bilayer system, the hybridisation between the out-of-plane orbitals and the hybridisation between the in-plane orbitals split the valence band respectively at the Gamma and K point. The splitting in the valence band is opened also without spin-orbit coupling and occurs due to the M-M and X-X hybridisation between the two monolayers. The transition from direct to indirect band gap is governed by the hybridisation between out-of-plane orbitals of different layers and in-plane orbitals of different layers.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)
Nyckelord
- Nanostructured semiconductors
- tight-binding Hamiltonians
- strained layers
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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