2009/08/27 by X. F. Sun, B. Lin, Bixia Lin +7
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.80.104510
published as Phys. Rev. B 80, 104510 (2009) · 7 pages, 4 figures, accepted for publication in Phys. Rev. B
arxiv created 2009/08/27 · openalex publication_date 2009/09/25 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
To investigate the validity of the Wiedemann-Franz (WF) law in disordered but metallic cuprates, the low-temperature charge and heat transport properties are carefully studied for a series of impurity-substituted and carrier-overdoped La1.8Sr0.2Cu_1\ensuremath-zMzO4 (M=Zn or Mg) single crystals. With moderate impurity substitution concentrations of z=0.049 and 0.082 (M=Zn), the resistivity shows a clear metallic behavior at low temperature and the WF law is confirmed to be valid. With increasing impurity concentration to z=0.13 (M=Zn) or 0.15 (M=Mg), the resistivity shows a low-T upturn but its temperature dependence indicates a finite conductivity in the T\ensuremath→0 limit. In this weakly localized metallic state, that is intentionally achieved in the overdoped regime, a negative departure from the WF law is found, which is opposite to the theoretical expectation.