Metal-insulator transition in lead yttrium ruthenate

被引:0
|
作者
Akhbarifar, Sepideh [1 ,2 ]
Lutze, Werner [1 ,2 ]
Mecholsky, Nicholas A. [1 ,2 ]
Pegg, Ian L. [1 ,2 ]
机构
[1] Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA
[2] Catholic Univ Amer, Vitreous State Lab, Washington, DC 20064 USA
关键词
Metal-insulator transition; Ruthenate pyrochlores; Electrical conductivity; Seebeck coefficients; Power factors; HIGH-PRESSURE SYNTHESIS; CRYSTAL-STRUCTURE; ELECTRICAL-PROPERTIES; OXIDE PYROCHLORES; BAND-STRUCTURE; RU;
D O I
10.1016/j.matchemphys.2020.124172
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Lead yttrium ruthenate pyrochlore solid solutions (Pb2-xYxRu2O6.5+z) were investigated for a metal insulator transition (MIT) and the Seebeck effect. Introducing increasing moles x of Y instead of Pb into metallic Pauli paramagnetic Pb2Ru2O6.5 causes an MIT at x approximate to 0.2 and formation of semiconductor/insulator materials until the antiferromagnetic Mott insulator Y2Ru2O7 is reached. The Mott-Hubbard mechanism of electron localization was used to explain the MIT. A critical content of yttrium is needed to open the Mott-Hubbard gap and to fill the lower Hubbard band (LHB) with localized t(2g)(4) electrons. The Seebeck effect showed a maximum between 400 and 500 K, for at least all x <= 1.5. The effect can be explained in terms of S varying proportionally with the effective mass of the carriers and inversely with their concentration.
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页数:6
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