Mott state and quantum critical points in rare-earth oxypnictides RO1-xFxFeAS (R= La, Sm, Nd, Pr, Ce)

G. Giovannetti, S. Kumar, J. van den Brink

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We investigate the magnetic phase diagram of the newly discovered iron-based high temperature oxypnictide superconductors of the type RO1-xFxFeAs, with rare earths R=La, Sm, Nd, Pr and Ce by means of ab initio SGGA and SGGA+U density functional computations. We find undoped LaOFeAs to be a Mott insulator when incorporating electronic correlations via SGGA+U for any physically relevant value of U. The doped compounds are according to SGGA conductors with a transition from an antiferromagnetic to a nonmagnetic state at a hole doping of concentration xc=0.075 for R=Nd, Pr and at electron doping xc=0.25 for Ce and 0.6 for Sm. Superconductivity in these rare-earth oxypnictides thus appears in the vicinity of a magnetic quantum critical point where electronic correlations are expected to play an important role because of the vicinity of a Mott insulating state at zero doping.
Original languageUndefined
Pages (from-to)3653-3657
Number of pages5
JournalPhysica B
Issue number19-20
Publication statusPublished - 2008


  • Quantum critical point
  • Mott insulator
  • METIS-250310
  • IR-79043
  • LaOFeAs

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