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Title: Infrared spectroscopy of the intermediate-valence semiconductor YbB{sub 12}

Abstract

The dynamic conductivity and permittivity spectra of the intermediate-valence compound YbB{sub 12} are measured in the frequency range (6-10{sup 4}) cm{sup -1} (quantum energy 0.75 meV-1.24 eV) at temperatures of 5-300 K. Analysis of the spectral singularities associated with the response of free charge carriers has made it possible for the first time to determine the temperature dependences of their microscopic parameters, viz., concentration, effective mass, relaxation frequency and time, mobility, and plasma frequency. It is shown that the relaxation frequency decreases upon cooling from 300 K to the coherence temperature T* = 70 K for YbB{sub 12}, which is mainly associated with the phonon mechanism of scattering of charge carriers. For cooling below the coherence temperature T* = 70 K, the temperature dependence of the relaxation frequency for charge carriers of the Fermi-liquid type is found to be {gamma} {approx} {gamma}{sub 0} + T{sup 2}, while their effective mass and relaxation time increase, respectively, to m*(20 K) = 34m{sub 0} (m{sub 0} is the free electron mass) and {tau}(20 K) = 4 x 10{sup -13} s, indicating the establishment of coherent scattering of carriers from localized magnetic moments of the f centers. At a temperature of T = 5more » K, the conductivity spectrum contains an absorption line at a frequency of 22 cm{sup -1} (2.7 meV); the origin of this line can be associated with the exciton-polaron bound state. Since such a state was observed earlier in other intermediate-valence semiconductors (such as SmB{sub 6}, TmSe{sub 1-x}Te, and (Sm, Y)S), it is probably typical of this class of compounds.« less

Authors:
; ; ;  [1];  [2];  [3]
  1. Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)
  2. Universitaet Stuttgart, Physikalisches Institut (Germany)
  3. Hiroshima University, Graduate School of ADSM (Japan)
Publication Date:
OSTI Identifier:
21067587
Resource Type:
Journal Article
Journal Name:
Journal of Experimental and Theoretical Physics
Additional Journal Information:
Journal Volume: 103; Journal Issue: 6; Other Information: DOI: 10.1134/S1063776106120077; Copyright (c) 2006 Nauka/Interperiodica; Article Copyright (c) 2006 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1063-7761
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; CHARGE CARRIERS; COHERENT SCATTERING; EFFECTIVE MASS; F CENTERS; INFRARED SPECTRA; LANGMUIR FREQUENCY; MAGNETIC MOMENTS; PERMITTIVITY; PHONONS; SAMARIUM BORIDES; SAMARIUM SULFIDES; SELENIUM TELLURIDES; SEMICONDUCTOR MATERIALS; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0000-0013 K; TEMPERATURE RANGE 0013-0065 K; TEMPERATURE RANGE 0065-0273 K; THULIUM TELLURIDES; YTTRIUM SULFIDES

Citation Formats

Gorshunov, B. P., E-mail: gorshunov@ran.gpi.ru, Prokhorov, A. S., Spektor, I. E., Volkov, A. A., Dressel, M., and Iga, F. Infrared spectroscopy of the intermediate-valence semiconductor YbB{sub 12}. United States: N. p., 2006. Web. doi:10.1134/S1063776106120077.
Gorshunov, B. P., E-mail: gorshunov@ran.gpi.ru, Prokhorov, A. S., Spektor, I. E., Volkov, A. A., Dressel, M., & Iga, F. Infrared spectroscopy of the intermediate-valence semiconductor YbB{sub 12}. United States. doi:10.1134/S1063776106120077.
Gorshunov, B. P., E-mail: gorshunov@ran.gpi.ru, Prokhorov, A. S., Spektor, I. E., Volkov, A. A., Dressel, M., and Iga, F. Fri . "Infrared spectroscopy of the intermediate-valence semiconductor YbB{sub 12}". United States. doi:10.1134/S1063776106120077.
@article{osti_21067587,
title = {Infrared spectroscopy of the intermediate-valence semiconductor YbB{sub 12}},
author = {Gorshunov, B. P., E-mail: gorshunov@ran.gpi.ru and Prokhorov, A. S. and Spektor, I. E. and Volkov, A. A. and Dressel, M. and Iga, F.},
abstractNote = {The dynamic conductivity and permittivity spectra of the intermediate-valence compound YbB{sub 12} are measured in the frequency range (6-10{sup 4}) cm{sup -1} (quantum energy 0.75 meV-1.24 eV) at temperatures of 5-300 K. Analysis of the spectral singularities associated with the response of free charge carriers has made it possible for the first time to determine the temperature dependences of their microscopic parameters, viz., concentration, effective mass, relaxation frequency and time, mobility, and plasma frequency. It is shown that the relaxation frequency decreases upon cooling from 300 K to the coherence temperature T* = 70 K for YbB{sub 12}, which is mainly associated with the phonon mechanism of scattering of charge carriers. For cooling below the coherence temperature T* = 70 K, the temperature dependence of the relaxation frequency for charge carriers of the Fermi-liquid type is found to be {gamma} {approx} {gamma}{sub 0} + T{sup 2}, while their effective mass and relaxation time increase, respectively, to m*(20 K) = 34m{sub 0} (m{sub 0} is the free electron mass) and {tau}(20 K) = 4 x 10{sup -13} s, indicating the establishment of coherent scattering of carriers from localized magnetic moments of the f centers. At a temperature of T = 5 K, the conductivity spectrum contains an absorption line at a frequency of 22 cm{sup -1} (2.7 meV); the origin of this line can be associated with the exciton-polaron bound state. Since such a state was observed earlier in other intermediate-valence semiconductors (such as SmB{sub 6}, TmSe{sub 1-x}Te, and (Sm, Y)S), it is probably typical of this class of compounds.},
doi = {10.1134/S1063776106120077},
journal = {Journal of Experimental and Theoretical Physics},
issn = {1063-7761},
number = 6,
volume = 103,
place = {United States},
year = {2006},
month = {12}
}