Erratum: Unconventional Pairing Originating from the Disconnected Fermi Surfaces of SuperconductingLaFeAsO1−xFx[Phys. Rev. Lett.101, 087004 (2008)]

Abstract

The appearance of the gap nodes intersecting the Fermi surface in Fig. 2(d) of our Letter was due to an error in the final stage of the calculation, i.e., the unitary transformation from the orbital representation (in which we have solved the Eliashberg equation) to the band representation. The correct Fig. 2 is shown below, where the main changes appear in (d), while (a),(b) are the same, and (c),(e) remain essentially unchanged as far as the features on the Fermi surface are concerned. The diagonal elements of the gap in the band representation is fully open on the Fermi surface [schematically the upper panel of Fig. 2(b)], and the off-diagonal elements are less important in this sense. However, the main conclusions of the original Letter related to this figure do remain unaltered in the following sense. (i) The magnitude of the gap along the Fermi surface still varies significantly. (ii) Regarding the way in which the gap nodes intersecting the Fermi surface appear depending on the parameter values, we do find that the nodes in the s-wave gap nearly touch or intersect the Fermi surface for band fillings beyond 6.3, or also when we adopt a band structure obtained for the theoretically optimized lattice parameters. This is consistent with the result recently obtained by Graser et al., who have adopted a five-band model obtained by fitting a band structure of the theoretically optimized lattice structure [1]. In these cases, d wave closely competes with or dominates over s wave. This can be naturally understood as a consequence of the coexistence of (, =2) and (, 0) spin fluctuations as asserted in the original Letter.

Magnetic order in orbital models of the iron pnictides

“…The former is comparable to the minimum energy (at the X points) of the band lying entirely above the Fermi surface; the latter is close to the difference between the hole bands and the Fermi energy at the M point. Since the η ν are the characteristic energies for the reconstruction of the electronic structure in the AFM state, it is therefore likely that these regions participate in the (π, π) AFM state, The five-orbital model of Kuroki et al 40 includes all five Fe d-orbitals. It was constructed by fitting to ab initio calculations for LaFeAsO, and it was one of the first orbital-based models proposed for the iron pnictides.…”

“…81 Although the existence of superconductivity in these models has been extensively studied, 40,[44][45][46]48,51,53,56,60,63,64,66 the magnetic behaviour remains rather poorly understood. The most popular approach to the appearance of AFM order in these models is to examine the ground state using a standard mean-field ansatz that allows for at most twosite magnetic unit cells; 47,50,52,54,58,59,61,64 very recently, this has been generalized to a Gutzwiller mean-field theory.…”

“…It is impossible to study each of the very many different orbital models proposed for the pnictides, and so in this paper we will restrict ourselves to five models: the two-orbital model of Raghu et al, 43 the three-orbital model of Daghofer et al, 59 the four-orbital model of Yu et al, 54 and the five-orbital models of Kuroki et al, 40 and Graser et al. 48 The main goal of this paper is to verify the appearance and explore the robustness of the stripe AFM order in the weak-coupling limit in these very different models, which have been selected as a representative sample of the different levels of sophistication available in the literature.…”

“…40,43,48,54,59 In all the proposed models, only on-site terms are included in the interaction Hamiltonian…”

Temperature insensitivity of Fermi surface in electron-doped high-temperature FeSe films on SrTiO3

“…An intriguing character of iron-based superconductors is their multiband nature which is believed to play an important role for antiferromagnetic and nematic orders in the non-doped parent compound and for high-temperature superconductivity in the doped compound [2]. Theoretical calculations for iron-based superconductors generally predict the formation of hole-like and electron-like Fermi surfaces at the Brillouin-zone center and corner, respectively [3][4][5]. While such multiband nature has been confirmed by experiments such as angle-resolved photoemission spectroscopy (ARPES) studies [6][7][8][9], there are some disagreements between the theoretical and experimental results and their origin remains unclear.…”