skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Directional Phonon Suppression Function as a Tool for the Identification of Ultralow Thermal Conductivity Materials

Authors:
;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1388401
DOE Contract Number:
SC0001299; FG02-09ER46577
Resource Type:
Journal Article
Resource Relation:
Journal Name: Scientific Reports; Journal Volume: 7; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute
Country of Publication:
United States
Language:
English
Subject:
solar (photovoltaic), solar (thermal), solid state lighting, phonons, thermal conductivity, thermoelectric, defects, mechanical behavior, charge transport, spin dynamics, materials and chemistry by design, optics, synthesis (novel materials), synthesis (self-assembly), synthesis (scalable processing)

Citation Formats

Romano, Giuseppe, and Kolpak, Alexie M. Directional Phonon Suppression Function as a Tool for the Identification of Ultralow Thermal Conductivity Materials. United States: N. p., 2017. Web. doi:10.1038/srep44379.
Romano, Giuseppe, & Kolpak, Alexie M. Directional Phonon Suppression Function as a Tool for the Identification of Ultralow Thermal Conductivity Materials. United States. doi:10.1038/srep44379.
Romano, Giuseppe, and Kolpak, Alexie M. Fri . "Directional Phonon Suppression Function as a Tool for the Identification of Ultralow Thermal Conductivity Materials". United States. doi:10.1038/srep44379.
@article{osti_1388401,
title = {Directional Phonon Suppression Function as a Tool for the Identification of Ultralow Thermal Conductivity Materials},
author = {Romano, Giuseppe and Kolpak, Alexie M.},
abstractNote = {},
doi = {10.1038/srep44379},
journal = {Scientific Reports},
number = ,
volume = 7,
place = {United States},
year = {Fri Mar 24 00:00:00 EDT 2017},
month = {Fri Mar 24 00:00:00 EDT 2017}
}
  • Pyrolytic carbon (PyC) is an important material used in many applications including thermal management of electronic devices and structural stability of ceramic composites. Accurate measurement of physical properties of structures containing textured PyC layers with few-micrometer thickness poses new challenges. Here a laser-based thermoreflectance technique is used to measure thermal conductivity in a 30-μm-thick textured PyC layer deposited using chemical vapor deposition on the surface of spherical zirconia particles. Raman spectroscopy is used to confirm the graphitic nature and characterize microstructure of the deposited layer. Room temperature radial and circumferential thermal conductivities are found to be 0.28 W m –1more » K –1 and 11.5 W m –1 K –1, corresponding to cross-plane and in-plane conductivities of graphite. While the anisotropic ratio of the in-plane to cross-plane conductivities is smaller than previous results, the magnitude of the smallest conductivity is noticeably smaller than previously reported values for carbon materials and offers opportunities in thermal management applications. Very low in-plane and cross-plane thermal conductivities are attributed to strong grain boundary scattering, high defect concentration, and small inter-laminar porosity. Lastly, experimental results agree with the prediction of thermal transport model informed by the microstructure information revealed by Raman spectroscopy.« less
  • The coefficients of the thermal conductivity (kappa) and first viscosity (eta) in thin helium films are evaluated explicitly as a function of temperature via phonon-phonon, phonon-roton, and roton-roton scattering. Above about 0.8 K, phonon-roton scattering and five-phonon processes are the main contributors to both coefficients. Below about 0.8 K, both coefficients increase exponentially with decreasing temperature. At temperatures below 0.3 K, kappa/sub ph/ has a T/sup -5/ dependence, while eta/sub ph/ shows exponential and T/sup -1/ dependencies. In the case of eta/sub ph/, the former is due to phonon-roton scattering and the latter originates from three-phonon processes. The coefficient kappa/submore » r/ from roton-roton scattering varies as T/sup -1/, and the roton part eta/sub r/ of the first viscosity is independent of temperature.« less
  • The effect of phonon-electron (p-e) scattering on lattice thermal conductivity is investigated for Cu, Ag, Au, Al, Pt, and Ni. We evaluate both phonon-phonon (p-p) and p-e scattering rates from first principles and calculate the lattice thermal conductivity (κ{sub L}). It is found that p-e scattering plays an important role in determining the κ{sub L} of Pt and Ni at room temperature, while it has negligible effect on the κ{sub L} of Cu, Ag, Au, and Al. Specifically, the room temperature κ{sub L}s of Cu, Ag, Au, and Al predicted from density-functional theory calculations with the local density approximation aremore » 16.9, 5.2, 2.6, and 5.8 W/m K, respectively, when only p-p scattering is considered, while it is almost unchanged when p-e scattering is also taken into account. However, the κ{sub L} of Pt and Ni is reduced from 7.1 and 33.2 W/m K to 5.8 and 23.2 W/m K by p-e scattering. Even though Al has quite high electron-phonon coupling constant, a quantity that characterizes the rate of heat transfer from hot electrons to cold phonons in the two-temperature model, p-e scattering is not effective in reducing κ{sub L} owing to the relatively low p-e scattering rates in Al. The difference in the strength of p-e scattering in different metals can be qualitatively understood by checking the amount of electron density of states that is overlapped with the Fermi window. Moreover, κ{sub L} is found to be comparable to the electronic thermal conductivity in Ni.« less