Flexural resonance mechanism of thermal transport across graphene-SiO2 interfaces
Abstract
Understanding the microscopic mechanism of heat dissipation at the dimensionally mismatched interface between a two-dimensional (2D) crystal and its substrate is crucial for the thermal management of devices based on 2D materials. Here, we study the lattice contribution to thermal (Kapitza) transport at graphene-SiO2 interfaces using molecular dynamics (MD) simulations and non-equilibrium Green's functions (NEGF). We find that 78 percent of the Kapitza conductance is due to sub-20 THz flexural acoustic modes, and that a resonance mechanism dominates the interfacial phonon transport. MD and NEGF estimate the classical Kapitza conductance to be hK ≈ 10 to 16 MW K−1 m−2 at 300 K, respectively, consistent with existing experimental observations. Taking into account quantum mechanical corrections, this value is approximately 28% lower at 300 K. Our calculations also suggest that hK scales as T2 at low temperatures (T < 100 K) due to the linear frequency dependence of phonon transmission across the graphene-SiO2 interface at low frequencies. Our study sheds light on the role of flexural acoustic phonons in heat dissipation from graphene to its substrate.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 19, 2018
- Source ID
- 10.1063/1.5020705
Entities
People
- Bo Qiu
- Eric Pop
- Shanglong Xu
- Xiulin Ruan
- Zhun-Yong Ong
Organizations
- Air Force Office of Scientific Research
- National Science Foundation
- Purdue University
- Stanford University