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Debye model
About: Debye model is a research topic. Over the lifetime, 7462 publications have been published within this topic receiving 133987 citations.
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TL;DR: Antonov et al. as discussed by the authors improved Antonov's lattice mechanical model for transition metals and tested its ability to reproduce a large number of lattice properties like binding energy, P-V relations, elastic constants and their pressure derivatives, interatomic interactions, phonon dispersion curves, temperature variation of Debye temperature, Debye-Waller factor and temperature variations of mean square displacement with fairly good success.
Abstract: A lattice mechanical model for transition metals, recently proposed by Antonov et al. has been improved. This improved model has been tested against its ability to reproduce a large number of lattice mechanical properties like binding energy, P–V relations, elastic constants and their pressure derivatives, interatomic interactions, phonon dispersion curves, temperature variation of Debye temperature, Debye–Waller factor and temperature variation of mean square displacement with fairly good success.
41 citations
01 Jan 1971
TL;DR: In this article, the Debye temperature for a number of refractory carbides were calculated from elastic constant data and then compared with those of Debye Temperature, θD, as derived from low-temperatureCP data.
Abstract: Values of the Debye temperature,θE, for a number of refractory carbides were calculated from elastic constant data and then compared with those of the Debye temperature,θD, as derived from low-temperatureCP data. It is found that an apparent discrepancy existed in the literature between the values ofθE andθD for these carbides. However, when the same units are used, agreement of 10 pct or better between the values ofθE andθD is found for all the carbides with the exception of MoC1/2. A discrepancy of 10 pct is reasonable based on an analysis of both the experimental and theoretical difficulties associated with the evaluation ofθE and θD for this class of materials. All the elastic constant data used were taken from the literature. Values ofCP for TiC, HfC, and WC were measured in the present study from 1.5° to 15°K. These values in addition to the literature data were used in derivingθD values. A correlation of the bulk modulus with interatomic spacing is presented for these refractory carbides. Based on this correlation, the bonding forces responsible for the cohesion of this class of materials are discussed.
41 citations
TL;DR: In this paper, the average electron-phonon coupling of Bi$_2$Te$_3$(111) was determined by adapting a recently developed quantum-theoretical derivation of the helium scattering probabilities to the case of degenerate semiconductors.
Abstract: We have studied the topological insulator Bi$_2$Te$_3$(111) by means of helium atom scattering. The average electron-phonon coupling $\lambda$ of Bi$_2$Te$_3$(111) is determined by adapting a recently developed quantum-theoretical derivation of the helium scattering probabilities to the case of degenerate semiconductors. Based on the Debye-Waller attenuation of the elastic diffraction peaks of Bi$_2$Te$_3$(111), measured at surface temperatures between $110~\mbox{K}$ and $355~\mbox{K}$, we find $\lambda$ to be in the range of $0.04-0.11$. This method allows to extract a correctly averaged $\lambda$ and to address the discrepancy between previous studies. The relatively modest value of $\lambda$ is not surprising even though some individual phonons may provide a larger electron-phonon interaction.
Furthermore, the surface Debye temperature of Bi$_2$Te$_3$(111) is determined as ${\rm \Theta}_D = (81\pm6)~\mbox{K}$. The electronic surface corrugation was analysed based on close-coupling calculations. By using a corrugated Morse potential a peak-to-peak corrugation of 9% of the lattice constant is obtained.
41 citations
TL;DR: In this paper, the dynamics of a mechanical subsystem interacting with a solid body is studied, where the Newton equations are transformed to a set of stochastic generalized Langevin equations describing the evolution of the coordinates of the subsystem particles.
Abstract: In this paper the dynamics of a mechanical subsystem interacting with a solid body is studied. The Newton equations are transformed to a set of stochastic generalized Langevin equations describing the evolution of the coordinates of the subsystem particles. The solid is modeled as a bath of interacting harmonic oscillators, and the effect of their spatial correlations on the statistical properties of the Langevin forces is accounted for. The most important result is the relation established between the static interaction of the subsystem with the solid body and the dissipative and fluctuation forces. In the particular case of a subsystem consisting of a single particle, an expression is derived for the friction tensor in terms of the static interaction potential and Debye cutoff frequency of the solid. The analysis is applied in the latter case to some simple processes occurring in solids, such as adsorption, desorption, and diffusion.
41 citations
TL;DR: In this paper, the specific heat of graphite intercalation compounds was analyzed in terms of electronic and lattice contributions, and the results showed that the electronic contribution of these compounds is at least 29 times above that for HOPG.
Abstract: The specific heat of the graphite intercalation compounds KC/sub 8/, CsC/sub 8/, and RbC/sub 8/ and their parent material, highly oriented pyrolytic graphite (HOPG), has been determined between 0.48 and 90 K. The results are analyzed in terms of electronic and lattice contributions. The electronic contribution to the specific heat of these compounds is enhanced by at least 29 times above that for HOPG. Comparisons are made to theoretical band-structure calculations. The lattice contribution shows deviations from a Debye model for T>5 K, which can be mathematically fitted by an Einstein specific-heat function. While our results for RbC/sub 8/ are unique, comparison with previous results for powder-based KC/sub 8/ and CsC/sub 8/ samples over a limited temperature range suggest that the type of parent graphite and/or details of preparation technique may influence the physical properties of these compounds.
41 citations