Spatial localization of holes in La sub(2 - x)Sr sub(x) CuO sub(4)

• Published in: Glass physics and chemistry Vol. 40; no. 6; pp. 635 - 642
• Main Authors: Marchenko, A V, Nikolaeva, A V, Doronin, V A, Seregin, N P
• Format: Journal Article
• Language: English
• Published: 01-11-2014
• Subjects: Cations; COPPER ALLOYS (40 TO 99.3 CU); COPPER OXIDE; Electric fields; ELECTRICAL CONDUCTIVITY; Glass; GLASSES; HOLES; MATHEMATICAL ANALYSIS; Mathematical models; Position (location); Strontium; Tensors
• ISSN: 1087-6596; 1608-313X
• DOI: 10.1134/S1087659614060066

The parameters of the tensor of the electric field gradient (EFG) in cation sites of the La sub(2 - x)Sr sub(x)CuO sub(4) lattice have been determined by the method of emission Mossbauer spectroscopy on super(57)Co( super(57)me), super(67)Cu( super(67)Zn), super(67)Ga( super(67)Zn), and super(155)Eu( super(155)Gd) isotopes. There is no quantitative agreement between the calculated (the pointcharge model) and experimental values of the main component of the tensor EFG V sub(zz), which is explained by the absence of the reliable data on the Sternheimer coefficients for Fe super(3+), Zn super(2+), and Gd super(3+) ions. Based on the comparison of the calculated and experimental dependences of V sub(zz) on x it was shown that the holes appearing during the substitution of La super(3+) for Sr super(2+) are localized preferably on the oxygen atoms that are in the same plane as the copper atoms, which is in agreement with the model discussed in the literature and assumes that the mechanism responsible for the high-temperature superconductivity of solid solutions La sub(2 - x)Sr sub(x)CuO sub(4) is the interaction between the conductivity electrons and two-atomic two-electron centers with negative correlation energy.