Surface electronic structure of the nonoxide perovskite superconductor (formula presented)

I. G. Kim, J. I. Lee, Arthur J Freeman

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The surface electronic structures of (formula presented) with both the MgNi terminated (MgNi-Term) and the CNi terminated (CNi-Term) surfaces were investigated using the all-electron full-potential linearized augmented plane-wave method within the generalized gradient approximation to density-functional theory. The calculated work function of MgNi-Term (formula presented) is lower than that of CNi-Term (formula presented) The number of total electrons at the surface layer of MgNi-Term is much decreased, while that of CNi-Term is less decreased than that of MgNi-Term, with respect to their center layers. The number of (formula presented) d electrons of MgNi-Term is calculated to be 0.08 electrons more than that of CNi-Term. The layer projected l-decomposed local density of states (DOS) show that the difference in the number of (formula presented) electrons is due to the strong (formula presented) and (formula presented) hybridization at the surface layer of CNi-Term. The peak just below the Fermi level (formula presented) in bulk (formula presented) is broadened substantially at the (formula presented) of CNi-Term, while that peak survives at (formula presented) of MgNi-Term. By analyzing the charge density belonging to a very narrow energy window just below (formula presented) such considerable modifications of the DOS peak at CNi-Term is seen to be due to the broken local symmetry of the CNi layer at the surface. It is considered that the behavior of the modification of the peak near (formula presented) resembles p-band hole doping through C-site substitution, supported by the stability against ferromagnetism determined from total-energy calculations. Superconductivity of the (formula presented) surface is discussed briefly in relation with the modifications of the DOS peak at (formula presented).

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number17
Publication statusPublished - Jan 1 2002

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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