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

Giovannetti, Gianluca and Kumar, Sanjeev and Brink van den, Jeroen (2008) Mott state and quantum critical points in rare-earth oxypnictides RO1-xFxFeAs (R=La,Sm,Nd,Pr,Ce). Physica B: Condensed matter, 403 (19-20). pp. 3653-3657. ISSN 0921-4526

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Abstract:	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.
Item Type:	Article
Copyright:	© 2008 Elsevier
Faculty:	Science and Technology (TNW)
Research Group:	Computational Materials Science (CMS)
Link to this item:	http://purl.utwente.nl/publications/79043
Official URL:	http://dx.doi.org/10.1016/j.physb.2008.06.008
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