A ring-source method to measure the thermal diffusivity of a conducting specimen in forced air flow: Study on aluminium

Omini, M.; Sparavigna, Amelia Carolina; Strigazzi, Alfredo; Teppati, G.

doi:10.1007/bf02453029

Cited by 39 publications

(78 citation statements)

References 34 publications

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“…In this work we demonstrate this behavior using a first principles approach, which combines accurate calculation of the harmonic and anharmonic interatomic force constants (IFCs) using density functional perturbation theory (DFPT) with an exact numerical solution to the PeierlsBoltzmann transport equation (PBE) for phonons [25,26,40,41]. Previous implementation of this approach for ambient pressure yielded excellent agreement with the measured thermal conductivities of silicon, germanium and diamond [25,26] with no adjustable parameters.…”

Section: Introductionmentioning

confidence: 83%

“…The phonon lifetime τ λα due to this scattering can be extracted from the solution of the linearized PBE [25,26,41,42], which can be cast as a set of coupled equations for τ λα :…”

Section: Ab Initio Transport Theorymentioning

confidence: 99%

“…The solution to the PBE, Eq. 1, has been described in detail elsewhere [25,26,40,41]. Here we focus on the physical significance of its components.…”

Section: Ab Initio Transport Theorymentioning

confidence: 99%

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Thermal conductivity of diamond under extreme pressure: A first-principles study

2012

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Using a first principles approach based on density functional perturbation theory and an exact numerical solution to the phonon Boltzmann equation, we show that application of large compressive hydrostatic pressure dramatically increases the thermal conductivity of diamond.We connect this enhancement to the overall increased frequency scale with pressure, which makes acoustic velocities larger and reduces phonon-phonon scattering rates. Of particular importance is the often neglected fact that heat-carrying acoustic phonons are coupled through lattice anharmonicity to higher frequency optic modes. An increase in optic mode frequencies with pressure weakens this coupling and contributes to driving the diamond thermal conductivities to far larger values than in any material at ambient pressure and temperature. 63.20.kg, 71.15Mb 2

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Section: Introductionmentioning

confidence: 83%

“…The phonon lifetime τ λα due to this scattering can be extracted from the solution of the linearized PBE [25,26,41,42], which can be cast as a set of coupled equations for τ λα :…”

Section: Ab Initio Transport Theorymentioning

confidence: 99%

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Thermal conductivity of diamond under extreme pressure: A first-principles study

2012

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“…In our first principles approach, the phonon frequencies and velocities are determined by diagonalizing the dynamical matrix, and the phonon transport lifetimes are PRL 111, 025901 (2013) Selected for a Viewpoint in Physics P H Y S I C A L R E V I E W L E T T E R S week ending 12 JULY 2013 calculated using an iterative solution of the linearized Boltzmann transport equation for phonons [15]. The only inputs are the harmonic and anharmonic interatomic force constants, which are obtained using density functional theory [16,17] and density functional perturbation theory [18].…”

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confidence: 99%

Keeping it Cool

Uher¹

2013

Physics

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We have calculated the thermal conductivities ( ) of cubic III-V boron compounds using a predictive first principles approach. Boron arsenide is found to have a remarkable room temperature over 2000 W m À1 K À1 ; this is comparable to those in diamond and graphite, which are the highest bulk values known. We trace this behavior in boron arsenide to an interplay of certain basic vibrational properties that lie outside of the conventional guidelines in searching for high materials, and to relatively weak phononisotope scattering. We also find that cubic boron nitride and boron antimonide will have high with isotopic purification. This work provides new insight into the nature of thermal transport at a quantitative level and predicts a new ultrahigh material of potential interest for passive cooling applications. DOI: 10.1103/PhysRevLett.111.025901 PACS numbers: 66.70.Àf, 63.20.kg, 71.15.Àm As microelectronic devices become smaller, faster, and more powerful, thermal management is becoming a critical challenge in, e.g., microprocessors, LEDs, and high power RF devices. As a result, the ability to identify and understand materials with high thermal conductivities ( ) is becoming increasingly important [1]. Carbon based materials, including diamond and graphite, have long been recognized as having the highest of any bulk material with room temperature (RT) values around 2000 W m À1 K À1 [2,3]. Other high materials, such as copper, are not even close, having four to five times smaller values [4]. However, diamond is scarce and its synthetic fabrication suffers from slow growth rates, high cost, and low quality [5]. Thus it is of current interest to identify new materials with ultrahigh thermal conductivities.Commonly accepted criteria [4] to guide the search for high nonmetallic crystals include (i) simple crystal structure, (ii) low average atomic mass, M av , (iii) strong interatomic bonding, and (iv) low anharmonicity. Items (ii) and (iii) imply a large Debye temperature, D , and give the frequently used rule of thumb that decreases with increasing M av and with decreasing D . However, little progress has been made over the years in identifying new high materials.Until recently fully microscopic, parameter-free computational materials techniques for electronic properties have been more advanced than are those for thermal transport. In the last few years quantitative ab initio techniques have been developed for thermal transport [6-12], and we have made contributions to this development [6,7,12]. These techniques open the way to a fuller understanding of the key physical features in thermal transport and to the ability to predict accurately the of new materials. Here, we present quantitative, first principles calculations of for the class of boron based cubic III-V compounds, boron nitride (BN), boron phosphide (BP), boron arsenide (BAs), and boron antimonide (BSb), referred to collectively as BX compounds. We find that BAs has an exceptionally high RT above 2000 W m À1 K À1 , which is comparable to that of the ...

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“…The BTE itself has been studied using numerous computation-intensive methods. [8][9][10][11][12][13] There exists a large body of work in using molecular dynamics (MD) and lattice dynamics (LD) approaches to predict thermal conductivity. [14][15][16][17][18][19][20] Despite the prevalence of atomistic modeling techniques, the ability to conveniently and analytically describe heat transfer phenomena remains invaluable.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Holland model for silicon phonon-phonon relaxation times using lattice dynamics calculations

Zhu

Romero

Sellan

et al. 2013

Journal of Applied Physics

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We assess the ability of the Holland model to accurately predict phonon-phonon relaxation times from bulk thermal conductivity values. First, lattice dynamics calculations are used to obtain phonon-phonon relaxation times and thermal conductivities for temperatures ranging from 10 K to 1000 K for Stillinger-Weber silicon. The Holland model is then fitted to these thermal conductivities and used to predict relaxation times, which are compared to the relaxation times obtained by lattice dynamics calculations. We find that fitting the Holland model to both total and mode-dependent thermal conductivities does not result in accurate mode-dependent phonon-phonon relaxation times. Introduction of Umklapp scattering for longitudinal modes resulted in improved prediction of mode-dependent relative contributions to thermal conductivity, especially at high temperatures. However, assumptions made by Holland regarding the frequency-dependence of phonon scattering mechanisms are found to be inconsistent with lattice dynamics data. Instead, we introduce a simple method based on using cumulative thermal conductivity functions to obtain better predictions of the frequency-dependence of relaxation times.

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A ring-source method to measure the thermal diffusivity of a conducting specimen in forced air flow: Study on aluminium

Cited by 39 publications

References 34 publications

Thermal conductivity of diamond under extreme pressure: A first-principles study

Thermal conductivity of diamond under extreme pressure: A first-principles study

Keeping it Cool

Assessment of the Holland model for silicon phonon-phonon relaxation times using lattice dynamics calculations

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