Vibrational spectra of amorphous clusters: Universal aspects
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)
We have performed extensive numerical computations on the vibrational spectra of isolated amorphous clusters of medium to large size and containing one or two types of atoms. The interaction potential is also varied to study possible universality. For all the potentials and cluster sizes we find that the cumulative density of states can be described very accurately by the same functional form over a large central region of the spectrum. This functional form contains only one scale of frequency. We also find that the statistical fluctuations of the spectra are described by the Gaussian orthogonal ensemble of random matrices. For the largest clusters this is tested to a very high degree of precision in the central region and to a somewhat lower degree for most of the rest of the spectrum. We put forward a conjecture regarding the domain of the space of local minima of the potential energy function where universality with respect to the density of states function may be expected.
- OSTI ID:
- 20719335
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 72, Issue 7; Other Information: DOI: 10.1103/PhysRevB.72.075401; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
ACCURACY
AMORPHOUS STATE
ATOMIC CLUSTERS
ATOMS
ENERGY-LEVEL DENSITY
FLUCTUATIONS
GAUSS FUNCTION
MATRICES
POTENTIAL ENERGY
POTENTIALS
RANDOMNESS
VIBRATIONAL STATES