Raman study of coupled electronic and phononic excitations in LuB12

JOURNAL OF ALLOYS AND COMPOUNDS

卷:704

Article

Ponosov, Yu. S.^1,2  Makhnev, A. A.¹  Streltsov, S. V.^1,2  Filipov, V. B.³  Shitsevalova, N. Yu.³ 

[1] RAS, UB, MN Mikheev Inst Met Phys, S Kovalevskaya Str 18, Ekaterinburg 620990, Russia

[2] Ural Fed Univ, Mira St 19, Ekaterinburg 620002, Russia

[3] Natl Acad Sci Ukraine, IN Frantsevich Inst Problems Mat Sci, 3 Krzhizhanovskogo St, UA-03680 Kiev, Ukraine

关键词: Inelastic light scattering;    Electron-phonon interactions;    Anharmonicity;    Rare earth alloys and compounds;   

DOI  :  10.1016/j.jallcom.2017.01.319

来源: Elsevier

【 摘 要 】

Electronic Raman scattering and optical phonon self-energies are studied on single crystals of LuB12 with different isotopic composition in the temperature region 10-650 K and at pressures up to 10 GPa. The shape and energy position of the spectral peaks depend on the magnitude of the probed wave vector, temperature, and symmetry of excitations. We simulated experimental spectra using electronic structure obtained in the density functional theory and taking into account the electron-phonon scattering. The emergence of a broad continuum in the spectra is identified with the inelastic scattering of light from the electronic intraband excitations. Their coupling to non-fully symmetric phonon modes is the source of both the Fano interference and temperature-dependent phonon self-energies. In addition, long wavelength vibrations of the boron atoms are in nonadiabatic regime, so the electronic contribution to their self-energies provides a temperature dependence that is similar to the anharmonic contribution. Comparison of calculation and experiment allowed us to determine the coupling constant lambda = 032, which gives correct critical temperature of the transition to the superconducting state. (C) 2017 Elsevier B.V. All rights reserved.

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