2014/07/14 by Xiaokun Gu, Ronggui Yang · 2 citations
Materials Science · Physics and Astronomy · #2D Materials and Applications #Advanced Thermoelectric Materials and Devices #Band gap #Boltzmann constant #Boltzmann equation #Phonon #Phonon scattering #Relaxation (psychology) #Scattering #Thermal conductivity #Thermal properties of materials #cond-mat.mtrl-sci
paper · pdf · doi:10.1063/1.4896685
published as Appl. Phys. Lett. 105 (2014) 131903 · 21 pages, 7 figures
arxiv created 2014/07/14 · openalex publication_date 2014/09/29 · arxiv updated 2014/09/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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, MX2 (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 WS2. 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.