Phonon Properties

Such differences in multiphonon relaxation rates are believed to be largely responsible for the strongly enhanced visible luminescence observed in low- 

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J. L. Erskine. CRC Crit. Rev. Solid State Mater. Sci. 13,311,1987. Recent review of scattering mechanisms, surface phonon properties, and improved instrumentation. 

Material response in THz frequency region, which corresponds to far- and mid-infrared electromagnetic spectrum, carries important information for the understanding of both electronic and phononic properties of condensed matter. Time-resolved THz spectroscopy has been applied extensively to investigate the sub-picosecond electron-hole dynamics and the coherent lattice dynamics simultaneously. In a typical experimental setup shown in Fig. 3.5, an... 

Vanderbilt D, Taole SH, Narasimhan S (1990) Anharmonic elastic and phonon properties of silicon, Phys Rev B 42(17) 11373-11374... 

At the time of a recent review [9], there remained very few examples of vibrational studies of adsorbate, or localised substrate modes, at metal oxide surfaces. By far the majority of studies concerned the characterisation by HREELS of phonon modes (such as Fuchs-Kliewer modes) pertaining to the properties of the bulk structure, rather than the surface, or to electronic transitions. Such studies have been excluded from this review in order to concentrate on the vibrational spectroscopy of surface vibrations on well-characterised metal oxide surfaces such as single crystals or epitaxially grown oxide films, for which there is now a substantial literature. Nevertheless, it is important to briefly describe the electronic and phonon properties of oxides in order to understand the constraints and difficulties in carrying out RAIRS and HREELS with sufficient sensitivity to observe adsorbate vibrations, and more localised substrate vibrational modes. 

Charlier J-C, Eklund PC, Zhu J, Ferrari AC (2008) Electron and phonon properties of graphene their relationship with carbon nanotubes. In Jorio A, Dresselhaus G, DresseUiaus MS (eds) Carbon nanotubes, vol 111, Topics in applied physics. Springer, Berlin/Heidelberg, pp 673-709... 

Nogi, N., T. Noda, and S. Tanaka. 2000. Phonon properties of isotopically modified 3-rhombohedral boron. J. Solid State Chem. 154 296-300. 

The above analysis of all IV compounds investigated so far with respect to elastic and phononic properties is summarized schematically in fig. 44. The... 

Presumably, the truth will be somewhere in between. If the electronic properties, N Ep) and (P), behave anomalously near 53 kbar, the phononic properties, i.e. (w ), will also be anomalous and vice versa. In the case of... 

Once a structure has been optimized, there is a wide range of properties that can be calculated in the solid state for comparison with experiment. Conversely, these properties can also be used in the empirical derivation of interatomic potentials as will be discussed later. The properties that are readily available can be divided into the categories of mechanical, electrical and phonon properties. All of them utilize the ability to readily determine higher order derivatives (usually second) to which the observables are related. 

Wagner V, Gundel S, Geurts J et al (1998) Optictil and acoustical phonon properties of BeTe. J Cryst Growth 184-185 1067-1071... 

Talwar DN, Vandevyver M (1990) Pressure-dependent phonon properties of III-V compound semiconductors. Phys Rev B 41 12129-12139... 

Both pseudopotentials were generated in Refs. 14,15 so as to reproduce the valence bands of GaAs no adjustment whatsoever was made to fit any phonon properties. Although more precise norm-con ry ng pseudopotentials have been introduced recently, with excellent results in subsequent calculations,... 

The combined force and stress theorems are necessary and sufficient to describe the general equation-of-state of a quantum system, i.e. the relations of force and stress to displacements and strain, and thus constitute a powerful tool in the study of structural and dynamic properties of matter. For example, phonon properties can be studied in great detail by imposing regular nuclear displacements and calculating the restoring forces. The reader is referred to the papers by Martin and by Kune (this volume). 

In the above analysis it is assumed that the atoms vibrate with a single frequency Q, as in the Einstein theory, whereas in a real crystal there is a distribution of vibrational frequencies with an appropriate cut-off, as considered in the Debye theory. In any case, it is clear that a measurement of the /-factor by Mossbauer spectroscopy can provide knowledge concerning phonon properties, such as their frequency distribution and density of states. Similar information can also be obtained from an analysis of the second-order Doppler shift. Unfortunately, the restriction imposed by the relative timescales, typically as discussed earlier, normally... 

Raman scattering is also capable of giving information on the phonon properties of TmSe. In fig. 71 we compare the Raman intensity of the trivalent Tmo.g7Se (Morke and... 

B Schreder, A Matemy, W Kiefer, T Ktimmell, G Bacher, A Forchel, G Landwehr. Length dependence of the O phonon properties in CdZnSe/ZnSe-quantum wires. Solid State Commun. 114 435-440, 2000. 

While there are no experimental data available for cubic ZnO at atmospheric pressure, ab initio calculations for phonon properties of cubic ZnO, which relied on experimental data of rocksalt ZnO studied under high pressures ( 8 GPa) as input parameters, have been undertaken [55]. The predictions by such an exercise for a>ro and cOlo lead to 235 cm and 528 cm, respectively, for cubic ZnO. The values are smaller than those obtained by extrapolating the IRSE analysis. However, it should be pointed out that both extrapolations follow the same trend in predicting phonon mode frequencies and that they are smaller than those of hexagonal ZnO. The width of phonon modes depends on sample quality and processes that lead to broadening. A discussion of phonon mode broadening parameters can be found in Ref. [26, 27]. 

This chapter has given an introduction to vibrations at bare elemental surfaces, namely, surface phonons. Owing to the low energy of surface phonons, thermal excitations at surfaces nearly always include a significant thermal population of surface phonons. Consequently, the thermal properties are closely linked to phonon properties. 

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