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Pis'ma v Zhurnal Èksperimental'noi i Teoreticheskoi Fiziki, 2008, Volume 88, Issue 7, Pages 531–533
(Mi jetpl245)
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This article is cited in 1 scientific paper (total in 1 paper)
CONDENSED MATTER
Normal and “Anomalous” isotope shifts of phonon frequencies in mono- and polyisotopic germanium crystals
V. P. Glazkova, A. S. Ivanovb, I. Kuldab, V. I. Ozhogina, V. A. Somenkova a Russian Research Centre Kurchatov Institute, pl. Akademika Kurchatova 1, Moscow, 123182, Russia
b Institut Laue-Langevin, Grenoble, France
Abstract:
The shifts of the phonon frequencies in 70Ge and 74Ge monoisotopic crystals have been studied using inelastic neutron scattering. It has been shown that the frequency shifts for all of the branches are normal, i.e., inversely proportional to √M. At the same time, the gap between acoustic and optical frequencies in monoisotopic crystals appears to be much wider (by about 2 meV in the [111] direction) than that in natural polyisotopic crystals containing “isotopic defects.” In this case, the phonon frequencies undergo “anomalous” shifts; i.e., the oscillation frequency of the heavier isotope is higher than that for the lighter isotope. The effect is in qualitative agreement with old theoretical calculations of the effect of mass defects on the phonon spectra of diatomic lattices.
Received: 26.06.2008 Revised: 20.08.2008
Citation:
V. P. Glazkov, A. S. Ivanov, I. Kulda, V. I. Ozhogin, V. A. Somenkov, “Normal and “Anomalous” isotope shifts of phonon frequencies in mono- and polyisotopic germanium crystals”, Pis'ma v Zh. Èksper. Teoret. Fiz., 88:7 (2008), 531–533; JETP Letters, 88:7 (2008), 458–460
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https://www.mathnet.ru/eng/jetpl245 https://www.mathnet.ru/eng/jetpl/v88/i7/p531
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Abstract page: | 249 | Full-text PDF : | 97 | References: | 48 |
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