Phonon and electron contributions to the thermal conductivity of 
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 epitaxial layers

Zheng, Qiye; Mei, Antonio B.; Tuteja, Mohit; Sangiovanni, Davide; Hultman, Lars; Petrov, I.; Greene, J. E.; Cahill, David G.

doi:10.1103/physrevmaterials.1.065002

Cited by 41 publications

(29 citation statements)

References 55 publications

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“…Recently, Mei et al [116] have utilized ab initio MD to prove that VN can be stabilized by anharmonic atomic vibrations in the B1 structure at~250 K. Indeed, it has been discovered from XRD measurements by Kubel et al [117] that, at room temperature, VN in the B1 structure is strongly anharmonic with atomic displacements randomly shuffled along the <111> crystallographic directions with respect to the ideal B1 lattice sites. These characteristics have been recently linked by Zheng et al [118] to electron-phonon coupling effects in the VN lattice thermal conductivity. In summary, we have shown how the concept of Kohn anomaly is related to phonon/electronic instability of the group VB transition metals upon compression and how this instability drives phase transformation in vanadium and leads to the anomaly reductions in the yield strengths of niobium and tantalum.…”

Section: Discussionmentioning

confidence: 84%

Kohn Anomaly and Phase Stability in Group VB Transition Metals

et al. 2018

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Abstract:In the periodic table, only a few pure metals exhibit lattice or magnetic instabilities associated with Fermi surface nesting, the classical examples being α-U and Cr. Whereas α-U displays a strong Kohn anomaly in the phonon spectrum that ultimately leads to the formation of charge density waves (CDWs), Cr is known for its nesting-induced spin density waves (SDWs). Recently, it has become clear that a pronounced Kohn anomaly and the corresponding softening in the elastic constants is also the key factor that controls structural transformations and mechanical properties in compressed group VB metals-materials with relatively high superconducting critical temperatures. This article reviews the current understanding of the structural and mechanical behavior of these metals under pressure with an introduction to the concept of the Kohn anomaly and how it is related to the important concept of Peierls instability. We review both experimental and theoretical results showing different manifestations of the Kohn anomaly in the transverse acoustic phonon mode TA (ξ00) in V, Nb, and Ta. Specifically, in V the anomaly triggers a structural transition to a rhombohedral phase, whereas in Nb and Ta it leads to an anomalous reduction in yield strength.

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Section: Discussionmentioning

confidence: 84%

Kohn Anomaly and Phase Stability in Group VB Transition Metals

et al. 2018

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“…Furthermore, as their carrier concentration is lower than that of traditional metals (e.g., Al and Cu), these conductive ceramics would have lower κ e . For instance, as studied by Cahill and co‐workers and Williams, electrical conductivity of TiC, VN x , TiN, and ZrN is about one order of magnitude lower than that of Cu and κ (with major contribution from κ e ) less than 40 W m −1 K −1 in the temperature range of 300 to 1000 K. Therefore, porous nanostructures made of refractory conductive ceramic could provide a good opportunity to achieve the dedicated balance in minimizing both κ e and κ rad as well as maintaining stable nanostructures for thermal superinsulation at high temperature.…”

Section: High‐temperature Thermal Transport In Porous Materialsmentioning

confidence: 99%

Advanced Materials for High‐Temperature Thermal Transport

Shin

Wang

Luo

et al. 2019

Adv Funct Materials

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High temperature processes are widely used in a variety of existing and emerging industrial and aerospace applications. The thermal properties of high‐temperature materials thus play an important role in controlling the thermal energy, as highlighted by successful applications of thermal barrier coating and aerogels. While thermal transport processes at room and low temperature have witnessed tremendous progress in the past two decades, particularly on the fronts of understanding basic heat transfer properties at the micro‐ and nanoscale, the understanding at high temperature is still at the nascent stage, owing to several unique features at high temperature, such as the dominant Umklapp scattering effect that can render a crystalline material amorphous‐like thermal properties, and the important radiation contribution at high temperature. This lack of systematic understanding, coupled with the challenges in maintaining high‐temperature stability in a large number of materials, has limited the development of materials to meet the thermal transport properties pertaining to several current and emerging high‐temperature applications. This Review is aimed at providing an overview of the basic mechanisms governing thermal transport processes at high temperature, to identify their unique features and challenges, and to explore opportunities in material research for high‐temperature thermal materials.

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“…Recently, high quality growth of thin films of stoichiometric vanadium nitride (VN) has been achieved on MgO substrates [51]. The k L extracted from measurements of the total thermal conductivity of VN [52] using the Wiedemann-Franz law and simple models for electronic structure and transport showed a relatively weak dependence on temperature in the 300K-550K…”

Section: First Principles Theorymentioning

confidence: 99%

Fermi Surface Nesting and Phonon Frequency Gap Drive Anomalous Thermal Transport

Ravichandran

Lindsay

et al. 2018

Phys. Rev. Lett.

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The lattice thermal conductivity, k L , of typical metallic and non-metallic crystals decreases rapidly with increasing temperature because phonons interact more strongly with other phonons than they do with electrons. Using first principles calculations, we show that k L can become nearly independent of temperature in metals that have nested Fermi surfaces and large frequency gaps between acoustic and optic phonons. Then, the interactions between phonons and electrons become much stronger than the mutual interactions between phonons, giving the fundamentally different k L behavior. This striking trend is revealed here in the group V transition metal carbides, vanadium carbide, niobium carbide and tantalum carbide and should also occur in several of other metal compounds. This work gives insights into the physics of heat conduction in solids and identifies a new heat flow regime driven by the interplay between Fermi surfaces and phonon dispersions.

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Phonon and electron contributions to the thermal conductivity of VNx epitaxial layers

Cited by 41 publications

References 55 publications

Kohn Anomaly and Phase Stability in Group VB Transition Metals

Kohn Anomaly and Phase Stability in Group VB Transition Metals

Advanced Materials for High‐Temperature Thermal Transport

Fermi Surface Nesting and Phonon Frequency Gap Drive Anomalous Thermal Transport

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