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Title: Unusual isotope effect on thermal transport of single layer molybdenum disulphide

Thermal transport in single layer molybdenum disulfide (MoS{sub 2}) is critical to advancing its applications. In this paper, we use molecular dynamics simulations with first-principles force constants to study the isotope effect on the thermal transport of single layer MoS{sub 2}. Through phonon modal analysis, we found that isotopes can strongly scatter phonons with intermediate frequencies, and the scattering behavior can be radically different from that predicted by conventional scattering model based on perturbation theory, where Tamura's formula is combined with Matthiessen's rule to include isotope effects. Such a discrepancy becomes smaller for low isotope concentrations. Natural isotopes can lead to a 30% reduction in thermal conductivity for large size samples. However, for small samples where boundary scattering becomes significant, the isotope effect can be greatly suppressed. It was also found that the Mo isotopes, which contribute more to the phonon eigenvectors in the intermediate frequency range, have stronger impact on thermal conductivity than S isotopes.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)
  2. School of Energy and Power Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074 (China)
  3. (HUST), Wuhan 430074 (China)
  4. (United States)
Publication Date:
OSTI Identifier:
22486044
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; MOLECULAR DYNAMICS METHOD; MOLYBDENUM; MOLYBDENUM ISOTOPES; MOLYBDENUM SULFIDES; PHONONS; SCATTERING; SIMULATION; SULFUR ISOTOPES; THERMAL CONDUCTIVITY