Interfacial thermal transport with strong system-bath coupling: A phonon delocalization effect
Name
PhysRevB.97.195437.pdf
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706.78 KB
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Author(s)
He, Dahai
Thingna, Juzar
Cao, Jianshu
Date Issued
May 2018
Journal
Physical Review B
Publisher
American Physical Society
Citation
He, Dahai et al. "Interfacial thermal transport with strong system-bath coupling: A phonon delocalization effect." Physical Review B 97, 19: 195437 © 2018 American Physical Society
Version
Final published version
Abstract
We study the effect of system-bath coupling strength on quantum thermal transport through the interface of two weakly coupled anharmonic molecular chains by using a quantum self-consistent phonon approach. The approach inherently assumes that the two segments (anharmonic molecular chains) are approximately in local thermal equilibrium with respect to the baths that they are connected to and transforms the strongly anharmonic system into an effective harmonic one with a temperature-dependent transmission. Despite the approximations, the approach is ideal for our setup, wherein the weak interfacial coupling guarantees an approximate local thermal equilibrium of each segment and short chain length (less than the phonon mean-free path) ensues from the effective harmonic approximation. Remarkably, the heat current shows a resonant to bi-resonant transition due to the variations in the interfacial coupling and temperature, which is attributed to the delocalization of phonon modes. Delocalization occurs only in the strong system-bath coupling regime and we utilize it to model a thermal rectifier whose ratio can be nonmonotonically tuned not only with the intrinsic system parameters but also with the external temperature.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.97.195437
