The diffusion of vacancies and self-interstices in crystals is accompanied by a strong change of local springs. We propose a theory, which takes into account this change. It is shown that the local softening of the lattice by a vacancy due to the breaking of bonds produce an enhancement of the contribution of low-frequency phonons, while the local hardening of the lattice by an interstitial atom leads to the opposite effect. As a consequence, at low temperatures the diffusion coefficient of vacancies is much smaller than that of interstitial atoms; the temperature dependences of these coefficients are also different. The obtained results are compared with experimental data for the diffusion of vacancies in helium crystals. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hizhnyakov, V., & Benedek, G. (2004). Quantum diffusion: effects of local distortion of phonons. PHYSICA STATUS SOLIDI C, 1(11), 3019-3022 [10.1002/pssc.200405329].

Quantum diffusion: effects of local distortion of phonons

BENEDEK, GIORGIO
2004

Abstract

The diffusion of vacancies and self-interstices in crystals is accompanied by a strong change of local springs. We propose a theory, which takes into account this change. It is shown that the local softening of the lattice by a vacancy due to the breaking of bonds produce an enhancement of the contribution of low-frequency phonons, while the local hardening of the lattice by an interstitial atom leads to the opposite effect. As a consequence, at low temperatures the diffusion coefficient of vacancies is much smaller than that of interstitial atoms; the temperature dependences of these coefficients are also different. The obtained results are compared with experimental data for the diffusion of vacancies in helium crystals. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Si
Articolo in rivista - Articolo scientifico
Scientifica
Solidi quantistici; diffusione quantistica
English
3019
3022
4
Hizhnyakov, V., & Benedek, G. (2004). Quantum diffusion: effects of local distortion of phonons. PHYSICA STATUS SOLIDI C, 1(11), 3019-3022 [10.1002/pssc.200405329].
Hizhnyakov, V; Benedek, G
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10281/13437
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