Spatial distribution of rare-earth ions and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>GaS</mml:mtext></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>tetrahedra in chalcogenide glasses studied via laser spectroscopy and<i>ab initio</i>molecular dynamics simulation
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説明
The spatial distribution of ${\text{Nd}}^{3+}$ ions and ${\text{GaS}}_{4}$ tetrahedral units in Nd-doped Ge-As-Ga-S glasses has been studied by laser spectroscopy and ab initio molecular dynamics (MD) simulations. A sharp increase in ${\text{Nd}}^{3+}$ fluorescence intensities and lifetimes was observed with increasing Ga content, and attributed to the formation of tightly bound ${\text{Nd}}^{3+}$ clusters in Ga-free glasses and the subsequent dissolution of such clusters upon Ga doping. A large modification in ${\text{Nd}}^{3+}$ sites was also identified from low-temperature site-selective excitation spectra, suggesting preferential spatial correlations between ${\text{Nd}}^{3+}$ and ${\text{GaS}}_{4}$ tetrahedra even at low Ga-doping levels. MD simulations of these materials in the liquid state showed a tendency for Ga cluster formation as well as spatial correlations between Nd and Ga atoms consistent with the experimental results. On the basis of this result, a comprehensive structural model for Nd- and Ga-doped sulfide glasses is proposed.
収録刊行物
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- Physical Review B
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Physical Review B 81 2010-03-16
American Physical Society (APS)