Neutron scattering study of coupled defect-phonon modes in KCl1-x(KCN)x

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Submitted on 1 Jan 1980

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Neutron scattering study of coupled defect-phonon modes in KCl1-x(KCN)x

R. Nicklow

To cite this version:

R. Nicklow. Neutron scattering study of coupled defect-phonon modes in KCl1-x(KCN)x. Journal de

Physique Colloques, 1980, 41 (C6), pp.C6-438-C6-438. �10.1051/jphyscol:19806113�. �jpa-00220020�

JOURNAL DE PHYSIQUE Collogue C6, supplkment au nO 7 , Tome 41, Juillet 1980, page C6-438

Neutron scattering study of coupled defect-phonon modes in KC1l-x(KCN)x

R. M. Nicklow, W. P. Cmmmett ("), R. F. Wood and M. Mostoller Oak Ridge National Laboratory (**), Oak Ridge, Tennessee 37830, U.S.A.

Abstract. - The hybridization of phonons with the internal modes of CN- impurities in KC1 has been studied by inelastic neutron scattering as a function of temperature between 10 K and 100 K for samplesrwith impurity concentrations in the range x ⁼ 0.4 to 6 %. The splitting of the ([[O) transverse acoustic phonon branch near 0.5 THz, observed previously (11 for x = 0.4 %, and the damping of the hybridized modes increase substantially with increasing concentration. The hybridization also shows a strong temperature dependence, essentially dis- appearing above 40 K for all the samples studied. Theoretical studies employing a simple two level impurity model [2] have also been carried out over the same ranges of concentration and temperature. The results are in reasonably good agreement with experiment at the lower concentrations, but the agreement deteriorates at the higher concentrations.

References

[l] WALTON, D., MOOK, H. A. and NJCKLOW, R. M., Phys. Rev. [2] WOOD, R. F. and MOSTOLLER, M., Phys. Rev. Lett. 39 (1977)

Lett 33 (1974) 412. 819.

(*) Present address : Montana State University, Bozeman, (**) Operated by Union Carbide Corporation under contract

.MT 59715, U.S.A. W-7405-eng-26 with the U.S. Department of Energy.

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19806113