Lattice dynamics in Bi2Te3and Sb2Te3: Te and Sb density of phonon states

AbstractSpecific features of the properties of Ga–P lattice vibrations have been investigated using the percolation model of a mixed Ga_1 – x Al_ x P crystal (alloy) with zero lattice mismatch between binary components of the alloy. In contrast to other two-mode alloy systems, in Ga_1 – x Al_ x P a percolation splitting of δ ~ 13 cm^–1 is observed for the low-frequency mode of GaP-like vibrations. An additional GaP mode (one of the percolation doublet components) split from the fundamental mode is observed for the GaP-rich alloy, which coincides in frequency with the gap corresponding to the zero density of one-phonon states of the GaP crystal. The vibrational spectrum of impurity Al in the GaP crystal has been calculated using the theory of crystal lattice dynamics. Upon substitution of lighter Al for the Ga atom, the calculated spectrum includes, along with the local mode, a singularity near the gap with the zero density of phonon states of the GaP crystal, which coincides with the mode observed experimentally at a frequency of 378 cm^–1 in the Ga_1 – x Al_ x P ( x < 0.4) alloy.

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LATTICE DYNAMICS OF YBa2Cu3O7 IN THE IONIC MODEL

International Journal of Modern Physics B ◽

10.1142/s0217979289000452 ◽

1989 ◽

Vol 03 (04) ◽

pp. 611-615 ◽

Cited By ~ 3

Author(s):

V. R. BELOSLUDOV ◽

M. Yu. LAVRENTIEV ◽

S. A. SYSKIN

Keyword(s):

Lattice Dynamics ◽

Short Range ◽

Phonon Dispersion ◽

Lattice Vibrations ◽

Coulombic Interaction ◽

Ionic Model ◽

Phonon Dispersion Curves ◽

Short Range Repulsion ◽

Ir And Raman ◽

Density Of Phonon States

A simple model of interatomic interactions in YBa 2 Cu 3 O 7, which takes into account long-range Coulombic interaction and short-range repulsion of the Born-Mayer type, is presented. On the basis of this model the calculation of lattice vibrations in YBa 2 Cu 3 O 7 is performed, and phonon dispersion curves and density of phonon states are found. A comparison with experimental data on IR and Raman spectra is presented.

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LATTICE DYNAMICS OF THE BINARY APERIODIC CHAINS OF ATOMS II: MULTIFRACTALITY OF PHONON SPECTRA

International Journal of Modern Physics B ◽

10.1142/s021797929500063x ◽

1995 ◽

Vol 09 (12) ◽

pp. 1453-1474 ◽

Cited By ~ 2

Author(s):

WŁODZIMIERZ SALEJDA

Keyword(s):

Lattice Dynamics ◽

Energy Spectra ◽

Legendre Transformation ◽

Model Parameters ◽

Local Scaling ◽

Multifractal Formalism ◽

Phonon Spectra ◽

Wide Range ◽

Multifractal Spectra ◽

Density Of Phonon States

The curdling of the phonon eigenvalues (PEV) on energy spectra of the binary generalized Fibonacci and non-Fibonaccian chains of atoms are numerically studied. A multifractal formalism based upon a new numerically efficient Legendre transformation from (q, τ) to (α, f) variables is proposed. The multifractal spectra of the normalized integrated density of phonon states (NIDOPS) for aperiodic chains of atoms are calculated in a wide range of model parameters. It is found out that the interval (α min , α max ) of magnitudes of the exponent α, determining the local scaling of the NIDOPS, shows a considerable shift to smaller values. This tendency is most pronounced for the NIDOPS of the so-called copper-mean, nickel-mean, structural circle and Rudin-Shapiro chain, where 0<α min <0.1. It is verified numerically that this effect is a manifestation of a strong curdling of PEV which take place in optical regions of the phonon spectra.

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