Directly visualizing the crossover from incoherent to coherent phonons in two-dimensional periodic MoS2/MoSe2 arrayed heterostructure. (October 2021)

• Record Type: Journal Article
• Authors: An, Meng; Chen, Dongsheng; Ma, Weigang; Hu, Shiqian; Zhang, Xing
• Is Part Of: International journal of heat and mass transfer. Volume 178(2021)
• Publication Date: 2021-10
• Subjects: MoS2/MoSe2 heterostructure -- Coherent phonon -- Non-equilibrium molecular dynamics simulation -- Thermal conductivity; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2021.121630
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: The coherent phonon transport can be destroyed and rebuilt through adjusting the density of MoSe2 nanodot arrays. Significant phonon localization induced by the destruction of correlation is visualized based on the spatial energy distribution and anharmonic analysis. The crossover from incoherent to coherent phonon transport is directly observed in atomic scale. Abstract: Recently, massive efforts have been done on controlling thermal transport via coherent phonons in the various periodic nanostructures. However, the intrinsic lattice difference between the constituent materials inevitably generates the disorder at the interfaces, thus limiting the opportunity of directly observing the coherent phonon transport. Here, we investigate the controllability and visualization of the coherent phonon transport in a periodic MoS2 /MoSe2 arrayed heterostructure with minimum lattice mismatching using non-equilibrium molecular dynamics simulation. It is found that the coherent phonon transport can be destroyed and rebuilt through adjusting the density of MoSe2 nanodot arrays. The phonon localization induced by the destruction of correlation is visualized based on the spatial energy distribution and anharmonic analysis. Furthermore, the eigen vector diagrams provide a distinct visualization of the localized phonon modes. Besides, the correlation of phonon can be rebuilt by reducing the period length, which is verified by the enhanced group velocities extracted from phonon dispersion curves. Interestingly, the crossover from incoherent to coherent phonon transport is directly observed by the spatial energy distributions and the spectral phonon transmission coefficients. Finally, the size and temperature dependence of thermal conductivity are also discussed. This study of the phonon coherence and its visualizing manipulation on thermal conductivity will be beneficial to fine heat control and management in the real applications. Graphical abstract: Image, graphical abstract