title: The Role of Interfacial Electronic Properties on Phonon Transport in Two-Dimensional MoS2on Metal Substrates.
abstract: We investigate the role of interfacial electronic properties on the phonon transport in two-dimensional MoS2adsorbed on metal substrates (Au and Sc) using first-principles density functional theory and the atomistic Green's function method. Our study reveals that the different degree of orbital hybridization and electronic charge distribution between MoS2and metal substrates play a significant role in determining the overall phonon-phonon coupling and phonon transmission. The charge transfer caused by the adsorption of MoS2on Sc substrate can significantly weaken the Mo-S bond strength and change the phonon properties of MoS2, which result in a significant change in thermal boundary conductance (TBC) from one lattice-stacking configuration to another for same metallic substrate. In a lattice-stacking configuration of MoS2/Sc, weakening of the Mo-S bond strength due to charge redistribution results in decrease in the force constant between Mo and S atoms and substantial redistribution of phonon density of states to low-frequency region which affects overall phonon transmission leading to 60% decrease in TBC compared to another configuration of MoS2/Sc. Strong chemical coupling between MoS2and the Sc substrate leads to a significantly (∼19 times) higher TBC than that of the weakly bound MoS2/Au system. Our findings demonstrate the inherent connection among the interfacial electronic structure, the phonon distribution, and TBC, which helps us understand the mechanism of phonon transport at the MoS2/metal interfaces. The results provide insights for the future design of MoS2-based electronics and a way of enhancing heat dissipation at the interfaces of MoS2-based nanoelectronic devices.
authors.affiliation: G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Zhequan
authors.initials: Z
authors.lastname: Yan
authors.affiliation: School of Energy and Power Engineering, Xi'an Jiaotong University , Xi'an, Shaanxi, P. R. China.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Mina
authors.initials: M
authors.lastname: Yoon
authors.affiliation: G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Satish
authors.initials: S
authors.lastname: Kumar
keywords: MoS2/metal interface; atomistic Green’s function; density functional theory; electron density; phonon transport; thermal boundary conductance