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      Temperature-dependent phonon spectrum of transition metal dichalcogenides calculated from the spectral energy density: lattice thermal conductivity as an application

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      Author(s)
      Mobaraki, Arash
      Sevik, C.
      Yapıcıoğlu, H.
      Çakır, D.
      Gülseren, Oğuz
      Date
      2019
      Source Title
      Physical Review B
      Print ISSN
      2469-9950
      Publisher
      American Physical Society
      Volume
      100
      Issue
      3
      Pages
      035402-6 - 035402-1
      Language
      English
      Type
      Article
      Item Usage Stats
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      231
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      Abstract
      Predicting the mechanical and thermal properties of quasi-two-dimensional (2D) transition metal dichalcogenides (TMDs) is an essential task necessary for their implementation in device applications. Although rigorous density-functional-theory–based calculations are able to predict mechanical and electronic properties, mostly they are limited to zero temperature. Classical molecular dynamics facilitates the investigation of temperature-dependent properties, but its performance highly depends on the potential used for defining interactions between the atoms. In this study, we calculated temperature-dependent phonon properties of single-layer TMDs, namely, MoS2, MoSe2, WS2, and WSe2, by utilizing Stillinger-Weber–type potentials with optimized sets of parameters with respect to the first-principles results. The phonon lifetimes and contribution of each phonon mode in thermal conductivities in these monolayer crystals are systematically investigated by means of the spectral-energy-density method based on molecular dynamics simulations. The obtained results from this approach are in good agreement with previously available results from the Green-Kubo method. Moreover, detailed analysis of lattice thermal conductivity, including temperature-dependent mode decomposition through the entire Brillouin zone, shed more light on the thermal properties of these 2D crystals. The LA and TA acoustic branches contribute most to the lattice thermal conductivity, while ZA mode contribution is less because of the quadratic dispersion around the Brillouin zone center, particularly in MoSe2 due to the phonon anharmonicity, evident from the redshift, especially in optical modes, by increasing temperature. For all the considered 2D crystals, the phonon lifetime values are compelled by transition metal atoms, whereas the group velocity spectrum is dictated by chalcogen atoms. Overall, the lattice thermal conductivity is linearly proportional with inverse temperature.
      Keywords
      Lattice thermal conductivity
      Phonons
      Thermal conductivity
      Thermal properties
      Transition metal dichalcogenide
      Permalink
      http://hdl.handle.net/11693/53151
      Published Version (Please cite this version)
      https://dx.doi.org/10.1103/PhysRevB.100.035402
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