Electro-vibrational coupling effects on “intrinsic friction” in transition metal dichalcogenides
Electro-vibrational coupling effects on “intrinsic friction” in transition metal dichalcogenides
We propose a protocol to disentangle the electro-vibrational structural coupling contributing to the intrinsic tribologic properties of layered MX2 transition metal dichalcogenides (M = Mo, W; X = S, Se, Te) under load. We employ ab initio techniques to model how changing the interlayer distance affects the electronic distribution and the vibrational properties of the system. We analyze the electro-vibrational coupling features by combining orbital polarization and mode Grüneisen parameters analyses with the recently developed bond covalency descriptor and the lattice dynamic metric named cophonicity. We find that intralayer charge distribution depends on the interlayer distance, determining, in turn, a shift of specific vibrational frequencies. We finally suggest a route to control the frequency shift, thus the bulk response to the load, in transition metal dichalcogenides through a proper selection of the atomic type.
106809-106818
Cammarata, Antonio
d9f02172-7364-4d80-a32b-03d2d7970257
Polcar, Tomas
c669b663-3ba9-4e7b-9f97-8ef5655ac6d2
Cammarata, Antonio
d9f02172-7364-4d80-a32b-03d2d7970257
Polcar, Tomas
c669b663-3ba9-4e7b-9f97-8ef5655ac6d2
Cammarata, Antonio and Polcar, Tomas
(2015)
Electro-vibrational coupling effects on “intrinsic friction” in transition metal dichalcogenides.
RSC Advances, 5 (129), .
(doi:10.1039/C5RA24837J).
Abstract
We propose a protocol to disentangle the electro-vibrational structural coupling contributing to the intrinsic tribologic properties of layered MX2 transition metal dichalcogenides (M = Mo, W; X = S, Se, Te) under load. We employ ab initio techniques to model how changing the interlayer distance affects the electronic distribution and the vibrational properties of the system. We analyze the electro-vibrational coupling features by combining orbital polarization and mode Grüneisen parameters analyses with the recently developed bond covalency descriptor and the lattice dynamic metric named cophonicity. We find that intralayer charge distribution depends on the interlayer distance, determining, in turn, a shift of specific vibrational frequencies. We finally suggest a route to control the frequency shift, thus the bulk response to the load, in transition metal dichalcogenides through a proper selection of the atomic type.
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Accepted/In Press date: 1 December 2015
e-pub ahead of print date: 7 December 2015
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Local EPrints ID: 412413
URI: http://eprints.soton.ac.uk/id/eprint/412413
ISSN: 2046-2069
PURE UUID: 340bb384-d74d-4943-a97e-a65278d420ce
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Date deposited: 17 Jul 2017 13:41
Last modified: 16 Mar 2024 04:08
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Author:
Antonio Cammarata
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