ARPES studies of the electronic structure of LaOFe(P,As)

Abstract

We report a comparison study of LaOFeP and LaOFeAs, two parent compounds of recently discovered iron-pnictide superconductors, using angle-resolved photoemission spectroscopy. Both systems exhibit some common features that are very different from well-studied cuprates. In addition, important differences have also been observed between these two ferrooxypnictides. For LaOFeP, quantitative agreement can be found between our photoemission data and the LDA band structure calculations, suggesting that a weak coupling approach based on an itinerant ground state may be more appropriate for understanding this new superconducting compound. In contrast, the agreement between LDA calculations and experiments in LaOFeAs is relatively poor, as highlighted by the unexpected Fermi surface topology around (π,π). Further investigations are required for a comprehensive understanding of the electronic structure of LaOFeAs and related compounds. : 74.25.Jb, PACS

Angle-resolved photoemission spectroscopy study of PrFeAsO0.7: Comparison with LaFePO

“…1 (b), the momentum regions with strong intensities are opposite between the large and small FS sheets around the Γ point, implying that they have different orbital characters. The large size of the hole pocket has been reported by the previous ARPES studies for the 1111 iron-based superconductors 13,17,18,22 and reflects heavily hole-doped electronic states. One can also observe clover-shaped FS's around the corner (the M point) of the 2D BZ.…”

“…Because the 1111 system has higher T c 's than those of the 122 system, detailed knowledge of their electronic structure and their differences from that of the 122 system may give a clue for understanding the mechanism of superconductivity in the iron-based superconductors. In the previous ARPES studies on the 1111 system 13,18 , heavily hole-doped electronic states have been observed probably due to the polar nature of the cleaved surfaces.…”

“…The ARPES observations mentioned above were mainly obtained for the so-called 122 system while only a few results have been reported for the 1111 system 13,17,18,22,23 owing to the difficulty in obtaining high quality, sizable single crystals. Because the 1111 system has higher T c 's than those of the 122 system, detailed knowledge of their electronic structure and their differences from that of the 122 system may give a clue for understanding the mechanism of superconductivity in the iron-based superconductors.…”

Topological surface states in paramagnetic and antiferromagnetic iron pnictides

“…22,23 In this case, surface bands result from the polar nature of these surfaces. 23 Surface states of this kind are not expected for LiFeAs and NaFeAs since the (001) surface of these compounds is not polar and they are indeed not seen by ARPES.…”

Temperature and doping dependence of normal state spectral properties in a two-orbital model for ferropnictides

“…These paths were chosen as they allow us to compare our results with available ARPES data, in particular those of Refs. 65,[72][73][74] . Concretely, we here show the evolution of the spectral function A( k, ω) as a function of momentum k, at low temperature: T = 20 K, and at half-filling: n = 2 (i.e.…”