Pb1-x Mnx Te and PbTe1-xSx compounds and their optical properties

Pb1-xMnxTe crystals were obtained by the Bridgman method and PbTe1-xSx crystals were grown by the vapour-liquid-solid technique. The structural properties of Pb1-xMnxTe (x?0.10) and PbTe 1-xSx(x?0.05) were observed by X-ray powder diffraction analysis. The optical properties were studied by Raman sp...

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Veröffentlicht in:Journal of the Serbian Chemical Society 2007, Vol.72 (1), p.55-62
Hauptverfasser: Trajic, Jelena, Golubovic, Aleksandar, Romcevic, Maja, Romcevic, Nebojsa, Nikolic, Slobodanka, Nikiforov, Vladimir
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Sprache:eng
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Zusammenfassung:Pb1-xMnxTe crystals were obtained by the Bridgman method and PbTe1-xSx crystals were grown by the vapour-liquid-solid technique. The structural properties of Pb1-xMnxTe (x?0.10) and PbTe 1-xSx(x?0.05) were observed by X-ray powder diffraction analysis. The optical properties were studied by Raman spectroscopy as a function of temperature. Measurements on these samples of different composition gave information about the Mn and S position in the lattice (off-centering), their clustering and ordering, as well as of the influence of these processes on the crystal structure and properties. The model of phonon behavior based on the Random Element Isodisplacement model was applied, and it was found that the phonons in PbTe 1-xSx show a two-mode behavior (each TO-LO mode pair of the end members degenerates to an impurity mode), while the Pb1-xMnxTe optical phonons have a intermediate one-two-mode behavior (the LO-mode frequency shifts continuously from PbTe to MnTe, while the other modes resemble the two-mode case). . Kristali Pb 1-xMnxTe su dobijeni metodom po Bridgman-u, a kristali PbTe 1-xSx su rasli pomocu tehnike gasovito-tecno-cvrsto. Strukturne osobine Pb 1-xMnxTe (x?0,10) i PbTe 1-xSx (x?0,05) su posmatrane rendgenskom difrakcijom praha. Opticke osobine su proucavane na razlicitim temperaturama pomoc u Raman spektroskopije. Merenja na razlicitim koncentracijama daju odgovore o polozajima Mn i S u resetki (off-centrima), njihovom klasterovanju, poretku kao i o njihovom uticaju na strukturu i osobine kristala. Primenjen je modifikovani REI model za ponasanje fonona kod cvrstih rastvora i nadjeno je da fononi u PbTe 1-xSx pokazuju dvo-modno ponasanje (svaki TO-LO mod krajnjih clanova se degenerise u primesni mod), dok Pb 1-xMnxTe opticki fononi imaju intermedijalno jedno-dvo-modno ponasanje (frekvencija LO-moda se kontinualno pomera od PbTe ka MnTe, dok drugi modovi zadrzavaju dvo-modno ponasanje). .
ISSN:0352-5139
1820-7421
DOI:10.2298/JSC0701055T