The Role of Interfacial Electronic Properties on Phonon Transport in Two-Dimensional MoS₂ on Metal Substrates

Abstract

We investigate the role of interfacial electronic properties on the phonon transport in two-dimensional MoS adsorbed 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 MoS and metal substrates play a significant role in determining the overall phonon-phonon coupling and phonon transmission. The charge transfer caused by the adsorption of MoS on Sc substrate can significantly weaken the Mo-S bond strength and change the phonon properties of MoS, 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 MoS/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 MoS/Sc. Strong chemical coupling between MoS and the Sc substrate leads to a significantly (∼19 times) higher TBC than that of the weakly bound MoS/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 MoS/metal interfaces. The results provide insights for the future design of MoS-based electronics and a way of enhancing heat dissipation at the interfaces of MoS-based nanoelectronic devices.

Phase transition and electronic structure investigation of MoS2-reduced graphene oxide nanocomposite decorated with Au nanoparticles

“…By doing this, both the Au(111) and 2H-MoS 2 unit cell is matched with the ideal lattice constant of 1T'-MoS 2 monolayers. We should mention that this five-layer model has been adopted in previous works describing well some features observed in experiments [40,41].…”

Thermal Transport in Two-Dimensional Heterostructures

“…Actually, this method was initially developed to handle quantum electron transport in nanostructures (Fan and Chen, 2010;Chen et al, 2018a;Deng et al, 2018;Zeng et al, 2018a;Chen et al, 2019a;Zhou et al, 2019;Fan et al, 2020). By making a few careful substitutions, the approach has been extended to study phonon transport in a wide variety of nanostructures (Xu et al, 2009;Peng and Chen, 2014;Zhou et al, 2017b;He et al, 2019) especially suitable for low-dimensional hetrostuctures such as Si/Ge (Tian et al, 2012b), graphene/h-BN (Peng et al, 2017), MoS 2 /metal (Yan et al, 2016b) interfaces and others (Ma et al, 2016). Here, we simply introduce this method from the numerical simulation point of view.…”

Covalent-bonding-induced strong phonon scattering in the atomically thin WSe2 layer

“…and Yan et al . suggested that these charge redistributions can perturb the pDOS of graphene and TMDs 11,12 . In this respect, the charge redistributions in the upper WSe 2 layer will have a strong influence on the thermal transport in the metal-TMD-insulator heterostructure, and such effect should appear differently depending on the bonding strength of the metal layer in contact with TMD materials.…”

“…Given the perfect crystalline quality of the interface, the thermal boundary resistance arises as a result of the scattering of the phonons which is due to the pDOS mismatch between the metal and WSe 2 layer 14 . As the metal-2D layer bonding becomes stronger, the pDOS of the 2D layer shifts toward that of the bonding material 11,12 , and hence the pDOS mismatch can be reduced leading to the enhancement of G( n = 1). In the same context, we can discuss the possible role of the WSe 2 /WSe 2 interface in the cross-plane thermal transport by comparing G( n = 2)/G( n = 1).…”

“…In addition, Yan et al . focused on the thermal transport through the metal/MoS 2 /metal junction with an AGF method 12 . They found that a strong bonding between the metal and TMD leads to an electron injection from metal to TMD, and the cross-plane thermal transport can be modulated as a result of the change in the pDOS.…”