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Title: Phonon transport in single-layer transition metal dichalcogenides: A first-principles study

Two-dimensional transition metal dichalcogenides (TMDCs) are finding promising electronic and optical applications due to their unique properties. In this letter, we systematically study the phonon transport and thermal conductivity of eight semiconducting single-layer TMDCs, MX{sub 2} (M = Mo, W, Zr, and Hf, X = S and Se), by using the first-principles-driven phonon Boltzmann transport equation approach. The validity of the single-mode relaxation time approximation to predict the thermal conductivity of TMDCs is assessed by comparing the results with the iterative solution of the phonon Boltzmann transport equation. We find that the phononic thermal conductivities of 2H-type TMDCs are above 50 W/mK at room temperature while the thermal conductivity values of the 1T-type TMDCs are much lower, when the size of the sample is 1 μm. A very high thermal conductivity value of 142 W/mK was found in single-layer WS{sub 2}. The large atomic weight difference between W and S leads to a very large phonon bandgap which in turn forbids the scattering between acoustic and optical phonon modes and thus resulting in very long phonon relaxation time.
Authors:
;  [1]
  1. Department of Mechanical Engineering and Materials Science and Engineering Program, University of Colorado at Boulder, Colorado 80309 (United States)
Publication Date:
OSTI Identifier:
22350788
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOLTZMANN EQUATION; CHALCOGENIDES; COMPUTERIZED SIMULATION; HAFNIUM COMPOUNDS; ITERATIVE METHODS; MASS NUMBER; MOLYBDENUM COMPOUNDS; PHONONS; RELAXATION TIME; SCATTERING; SELENIUM COMPOUNDS; SULFUR COMPOUNDS; TEMPERATURE RANGE 0273-0400 K; THERMAL CONDUCTIVITY; TRANSITION ELEMENT COMPOUNDS; TUNGSTEN COMPOUNDS; TUNGSTEN SULFIDES; TWO-DIMENSIONAL CALCULATIONS; ZIRCONIUM COMPOUNDS