Green function, quasi-classical Langevin and Kubo–Greenwood methods in quantum thermal transport

H. Sevinçli*, S. Roche, G. Cuniberti, Mads Brandbyge, R. Gutierrez, L. Medrano Sandonas

*Corresponding author for this work

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Abstract

With the advances in fabrication of materials with feature sizes at the order of nanometers, it has been possible to alter their thermal transport properties dramatically. Miniaturization of device size increases the power density in general, hence faster electronics require better thermal transport, whereas better thermoelectric applications require the opposite. Such diverse needs bring new challenges for material design. Shrinkage of length scales has also changed the experimental and theoretical methods to study thermal transport. Unsurprisingly, novel approaches have emerged to control phonon flow. Besides, ever increasing computational power is another driving force for developing new computational methods. In this review, we discuss three methods developed for computing vibrational thermal transport properties of nano-structured systems, namely Green function, quasi-classical Langevin, and Kubo–Green methods. The Green function methods are explained using both nonequilibrium expressions and the Landauer-type formula. The partitioning scheme, decimation techniques and surface Green functions are reviewed, and a simple model for reservoir Green functions is shown. The expressions for the Kubo–Greenwood method are derived, and Lanczos tridiagonalization, continued fraction and Chebyshev polynomial expansion methods are discussed. Additionally, the quasi-classical Langevin approach, which is useful for incorporating phonon–phonon and other scatterings is summarized.
Original languageEnglish
Article number273003
JournalJournal of Physics: Condensed Matter
Volume31
Issue number27
Number of pages29
ISSN0953-8984
DOIs
Publication statusPublished - 2019

Keywords

  • Quantum thermal transport
  • Green function method
  • Kubo–Greenwood methods
  • Quasi-classical Langevin

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