Role of crystal structure and junction morphology on interface thermal conductance

Article
Authors:Polanco, Carlos A. , Department of Electrical and Computer EngineeringUniversity of Virginia Rastgarkafshgarkolaei, Rouzbeh , Department of Mechanical and Aerospace EngineeringUniversity of Virginia Zhang, Jingjie, Department of Electrical and Computer EngineeringUniversity of Virginia Le, Nam Q. , Department of Mechanical and Aerospace EngineeringUniversity of Virginia Norris, Pamela, Department of Mechanical and Aerospace Engineering University of Virginia Hopkins, Patrick, Department of Mechanical and Aerospace Engineering University of Virginia Ghosh, Avik, Department of Electrical and Computer Engineering University of Virginia
Abstract:

We argue that the relative thermal conductance between interfaces with different morphologies is controlled by crystal structure through Mmin/Mc > 1, the ratio between the minimum mode count on either side Mmin, and the conserving modes Mc that preserve phonon momentum transverse to the interface. Junctions with an added homogenous layer, “uniform,” and “abrupt” junctions are limited to Mc, while junctions with interfacial disorder, “mixed,” exploit the expansion of mode spectrum to Mmin. In our studies with cubic crystals, the largest enhancement of conductance from “abrupt” to “mixed” interfaces seems to be correlated with the emergence of voids in the conserving modes, where Mc = 0. Such voids typically arise when the interlayer coupling is weakly dispersive, making the bands shift rigidly with momentum. Interfacial mixing also increases alloy scattering, which reduces conductance in opposition with the mode spectrum expansion. Thus the conductance across a “mixed” junction does not always increase relative to that at a “uniform” interface.

Rights:
All rights reserved (no additional license for public reuse)
Language:
English
Source Citation:

Polanco, Carlos A., Rouzbeh Rastgarkafshgarkolaei, Jingjie Zhang, Nam Q. Le, Pamela M. Norris, Patrick E. Hopkins, and Avik W. Ghosh. "Role of crystal structure and junction morphology on interface thermal conductance." Physics Review B 92.14 (2015): 144302-1-144302-10. Available: https://doi.org/10.1103/PhysRevB.92.144302

Publisher:
American Physical Society
Published Date:
October 5, 2015