[Zurück]

K. Nouneh, I.V. Kityk, R. Viennois, S. Benet, S. Charar, S. Paschen, K. Ozga:
"Influence of an electron-phonon subsystem on specific heat and two-photon absorption of the semimagnetic semiconductors Pb_1-xYb_xX (X=S, Se,Te) near the semiconductor-isolator phase transformation";
Physical Review B, 73 (2006), S. 035329-1 - 035329-8.

Influence of an electron-phonon subsystem on specific heat and two-photon absorption of the semimagnetic semiconductors Pb_1-xYb_xX (X=S, Se,Te) near the semiconductor-isolator phase transformation

K. Nouneh,1,2 I. V. Kityk,3 R. Viennois,2,5 S. Benet,1 S. Charar,2 S. Paschen,5 and K. Ozga4
1Laboratoire de Physique Appliquée et Automatique, Université de Perpignan, 52 Avenue Paul Alduy, Perpignan, France
2Groupe d'Etude des Semiconducteurs, CNRS-UMR 5650, Université Montpellier II, Pl. Eugène Bataillon, 34095 Montpellier Cedex 5, France
3Institute of Physics, J. Dlugosz University of Czestochowa, Aleja Aermii Krajowej 13/15, Czestochowa, Poland
4Institute of Biology and Biophysics, Technical University Czestochowa, Aleja Armii Krajowej 36, Czestochowa, Poland
5Max-Planck-Institut für Chemische Physik Fester Stoffe, Nöthnitzer Strasse 40, 01185 Dresden, Germany

(Received 23 March 2005; revised 18 November 2005; published 26 January 2006)

Specific heat, transport, and two-photon absorption (TPA) effects were studied in single crystalline magnetic semiconductors Pb1-xYbxX (X=S, Se,Te at x=1-3%) near semiconductor-isolator phase transitions. It was shown that the TPA may be used as a sensitive tool for investigations of electron-phonon interactions near low temperature semiconductor-isolator phase transformation. Comparison with other methods of phase transition studies has shown more sharplike temperature dependence of the TPA. Particularly, comparison with piezo-optical and dilatometric methods shows on a better temperature resolution of the TPA with respect to the phase transitions. It was established as a correlation between the density of low-temperature phonon modes and values of the TPA. Particularly with increasing of the electron-phonon interactions defined by the temperature-dependent Debye term (parameter beta) from the equation C=gammaT+betaT3+[summation]_{i = 1}ⁿdeltaiT2i+3, one can observe an increase of the TPA oscillator strengths. It was shown that only the low-temperature TPA behaviors might be determined by the features of the low-energy phonon modes related to the observed phase transformation. We also have discovered that low-temperature dependence of the specific heat Cp in Pb1-xRxTe (R=Yb,Te) with x=2.6% and 1.65%, respectively, exhibits a nonmagnetic ordering caused by large value of electron-phonon contribution. Applying magnetic fields up to 2 T substantially modifies the temperature features of several phonon low-frequency modes, which may indicate a contribution of magnons.

http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC06588177

http://dx.doi.org/10.1103/PhysRevB.73.035329