Intrinsic to extrinsic phonon lifetime transition in a GaAs–AlAs superlattice
Name
Nelson_Intrinsic to extrinsic.pdf
Size
5.02 MB
Format
Adobe PDF
Checksum (MD5)
2d8a8f5d1e4de7fc3953417375e50759
Author(s)
Hofmann, Felix
Garg, Jivtesh
Maznev, Alexei
Jandl, Adam Christopher
Bulsara, Mayank
Fitzgerald, Eugene A.
Chen, Gang
Nelson, Keith Adam
Date Issued
July 2013
Journal
Journal of Physics: Condensed Matter
Publisher
IOP Publishing
Citation
Hofmann, F, J Garg, A A Maznev, A Jandl, M Bulsara, E A Fitzgerald, G Chen, and K A Nelson. “Intrinsic to extrinsic phonon lifetime transition in a GaAs–AlAs superlattice.” Journal of Physics: Condensed Matter 25, no. 29 (July 24, 2013): 295401.
Version
Original manuscript
Abstract
We have measured the lifetimes of two zone-center longitudinal acoustic phonon modes, at 320 and 640 GHz, in a 14 nm GaAs/2 nm AlAs superlattice structure. By comparing measurements at 296 and 79 K we separate the intrinsic contribution to phonon lifetime determined by phonon–phonon scattering from the extrinsic contribution due to defects and interface roughness. At 296 K, the 320 GHz phonon lifetime has approximately equal contributions from intrinsic and extrinsic scattering, whilst at 640 GHz it is dominated by extrinsic effects. These measurements are compared with intrinsic and extrinsic scattering rates in the superlattice obtained from first-principles lattice dynamics calculations. The calculated room-temperature intrinsic lifetime of longitudinal phonons at 320 GHz is in agreement with the experimentally measured value of 0.9 ns. The model correctly predicts the transition from predominantly intrinsic to predominantly extrinsic scattering; however the predicted transition occurs at higher frequencies. Our analysis indicates that the 'interfacial atomic disorder' model is not entirely adequate and that the observed frequency dependence of the extrinsic scattering rate is likely to be determined by a finite correlation length of interface roughness.
MIT Department
Massachusetts Institute of Technology. Materials Processing Center
Massachusetts Institute of Technology. Department of Chemistry
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike 3.0
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/0953-8984/25/29/295401
