Correlation-induced self-doping in intercalated iron-pnictide superconductor Ba2Ti2Fe2As4O

Abstract

The electronic structure of the intercalated iron-based superconductor Ba2Ti2Fe2As4O (Tc - 21.5 K) has been investigated by using angle-resolved photoemission spectroscopy and combined local density approximation and dynamical mean field theory calculations. The electronic states near the Fermi level are dominated by both the Fe 3d and Ti 3d orbitals, indicating that the spacing layers separating different FeAs layers are also metallic. By counting the enclosed volumes of the Fermi surface sheets, we observe a large self-doping effect, i.e. 0.25 electrons per unit cell are transferred from the FeAs layer to the Ti2As2O layer, leaving the FeAs layer in a hole-doped state. This exotic behavior is successfully reproduced by our dynamical mean field calculations, in which the self-doping effect is attributed to the electronic correlations in the Fe 3d shell. Our work provides an alternative route of effective doping without element substitution for iron-based superconductors.

5 pages, 3 figures + Supplementary material

References in corpus (12)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Superconductivity at 22 K in Co-doped BaFe2As2 Crystals
• Dynamical Mean-Field Theory within an Augmented Plane-Wave Framework: Assessing Electronic Correlations in the Iron Pnictide LaFeAsO
• Superconductivity up to 30 K in the vicinity of quantum critical point in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• A precise method for visualizing dispersive features in image plots
• Theoretical evidence for strong correlations and incoherent metallic state in FeSe
• Superconductivity induced by ruthenium substitution in an iron arsenide: investigation of SrFe2-xRuxAs2 (0 <= x <= 2)
• Extraordinary quasiparticle scattering and bandwidth-control by dopants in iron-based superconductors
• Dynamical correlations and screened exchange on the experimental bench: spectral properties of the cobalt pnictide BaCo2As2
• Self doping effect and successive magnetic transitions in superconducting Sr${}_2$VFeAsO${}_3$
• Electronic band structure of BaCo${}_2$As${}_2$: a fully-doped ferropnictide with reduced electronic correlations
• Universal pair-breaking in transition metal-substituted iron-pnictide superconductors

Cited by in corpus (2)

• Spectral functions of Sr${}_2$IrO${}_4$: theory versus experiment
• Self-Optimized Superconductivity Attainable by Interlayer Phase Separation at Cuprate Interfaces