Lattice dynamics of solid neon at 6.5 and 23.7 K

Endoh, Y.; Shirane, G.; Skalyo, J.

doi:10.1103/physrevb.11.1681

Cited by 67 publications

(32 citation statements)

References 26 publications

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“…Under this condition lattice theories can give reasonable description of the phonon dispersions [3]. The rare gas solids [8][9][10][11] and CsCl [12] are examples of a vanishing Debye boson-phonon interaction. For these solids the acoustic phonons are perfectly described by sine functions of wave vector.…”

Section: Analysis Of Experimental Datamentioning

confidence: 99%

On the Distinction between Debye Bosons and Phonons

Köbler¹

2015

Int. J. Thermo

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A method is described that allows one to construct the dispersion of the Debye bosons (sound waves) from the known temperature dependence of the sound velocities. The method simply assumes that the sound velocity measured at temperature T gives the slope of the dispersion relation at excitation energy E = kBT. The associated reduced wave vector is set equal to q/q0 = a0kBT/hvL/T. In this way the dispersion of the Debye bosons can be constructed for all thermal energies for which sound velocities vL/T(T) are known. This can be up to melting temperature. Surprisingly, for metals and for insulators the dispersion of the Debye bosons can continue up to wave vector values of several times the zone boundary. At melting temperature the wavelength of the Debye bosons is of the order of the atomic diameters. The sources of the Debye bosons therefore must have atomic dimensions. Spontaneous generation of Debye bosons by individual atoms is, however, a completely unexplored process. Interactions with the atomistic background of phonons or lattice defects provide damping to the Debye bosons and make the material specific sound velocity vL/T(T) additionally sample and temperature dependent. For practically all solids it is observed that elastic constants and vL/T(T) decrease as a function of increasing temperature. For high energies the dispersion relation of the Debye bosons therefore becomes visibly lower than linear. Interactions between Debye bosons and phonons can modify the dispersion of the acoustic phonons appreciably. Because of their different symmetries the dispersion relations of Debye bosons and acoustic phonons can attract each other. It is observed that for low wave vector values the dispersion of the acoustic phonons can assume the linear wave vector dependence of the Debye bosons. At the end of the linear section a functional crossover to a sine-like function of wave vector occurs.

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Section: Analysis Of Experimental Datamentioning

confidence: 99%

On the Distinction between Debye Bosons and Phonons

Köbler¹

2015

Int. J. Thermo

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“…subject, as before, to q ---k' -k + K. In (28), VM-r is the MT version (i.e., the l = 0 partial wave) of the last three terms of the lhs of (19), ~ is the volume of the MT sphere (assuming a monatomic crystal), and ir is the unit vector for r. One matter not treated by Golibersuch was the problem of MT sphere overlap. Kenney 21 argued that the MT sphere should be reduced modestly from the touching-spheres radii in order to allow rigid-MT motion without sphere overlap.…”

Section: Specificsmentioning

confidence: 99%

“…Here we record the results. It is helpful to use the eq~ 9 i, scalar product which appears in the MT EPME (28) to separate the x, y, and z contributions with respect to a convenient axis system. Thus we conceive of the EPME as a vector, or Obviously these expressions are quite intricate.…”

Section: Computational Mattersmentioning

confidence: 99%

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Energy band theory and the lattice dynamics of rare gas crystals

Worth

Trickey

1980

J Low Temp Phys

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The results of a simple local-density energy band model (XoO are used to carry through a calculation of the phonon dispersion relations in fcc Ne and At. Adiabatic phonons, calculated from the computed Xa total energy surface, are perturbed by the Fr6hlich Hamiltonian with electron-phonon matrix elements calculated from the Xa energy bands. The use of low-order perturbation theory gives results in fair comparison with observed values, but shows the general scheme to be feasible. Except for questions of the exact physical content of the Xa model itself, the calculation is entirely ab initio, and is believed to be the first such achieved in insulators.

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“…Typically this might be found in disordered materials. 11 Increasingly we are seeing measurements of the density of states using neutron or x-ray scattering 12 being used as a probe of variations of phonon frequencies with parameters such as temperature, particularly when single crystals for full measurements of dispersion curves are not available.…”

Section: Density Of Statesmentioning

confidence: 99%

Introduction to the theory of lattice dynamics

Dove

2011

JDN

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Abstract. We review the theory of lattice dynamics, starting from a simple model with two atoms in the unit cell and generalising to the standard formalism used by the scientific community today. The key component of the theory is the force between atoms, and we discuss how this can be computed from empirical or quantum mechanical models. The basic model is developed to link the amplitudes of vibrations to thermodynamics. The major method for measuring lattice dynamics is inelastic scattering of beams of neutrons and x-rays. We develop a simplified theory of inelastic scattering of radiation beams, and show how this can be used in instrumentation. Several examples are used to illustrate the theory.

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Lattice dynamics of solid neon at 6.5 and 23.7 K

Cited by 67 publications

References 26 publications

On the Distinction between Debye Bosons and Phonons

On the Distinction between Debye Bosons and Phonons

Energy band theory and the lattice dynamics of rare gas crystals

Introduction to the theory of lattice dynamics

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