In the hole-doped cuprates, a small number of carriers suppresses antiferromagnetism and induces superconductivity. In the electron-doped cuprates, on the other hand, superconductivity appears only in a narrow window of high-doped Ce concentration after reduction annealing, and strong antiferromagnetic correlation persists in the superconducting phase. Recently, Pr1.3−xLa0.7CexCuO4 (PLCCO) bulk single crystals annealed by a protect annealing method showed a high critical temperature of around 27 K for small Ce content down to 0.05. Here, by angle-resolved photoemission spectroscopy measurements of PLCCO crystals, we observed a sharp quasi-particle peak on the entire Fermi surface without signature of an antiferromagnetic pseudogap unlike all the previous work, indicating a dramatic reduction of antiferromagnetic correlation length and/or of magnetic moments. The superconducting state was found to extend over a wide electron concentration range. The present results fundamentally challenge the long-standing picture on the electronic structure in the electron-doped regime.

Correlations between ten-channel EEGs obtained from thirteen healthy adult participants were investigated. Signals were obtained in two behavioral states: eyes open no task and eyes closed no task. Four time domain measures were compared: Pearson product moment correlation, Spearman rank order correlation, Kendall rank order correlation and mutual information. The psychophysiological utility of each measure was assessed by determining its ability to discriminate between conditions. The sensitivity to epoch length was assessed by repeating calculations with 1, 2, 3, …, 8 s epochs. The robustness to noise was assessed by performing calculations with noise corrupted versions of the original signals (SNRs of 0, 5 and 10 dB). Three results were obtained in these calculations. First, mutual information effectively discriminated between states with less data. Pearson, Spearman and Kendall failed to discriminate between states with a 1 s epoch, while a statistically significant separation was obtained with mutual information. Second, at all epoch durations tested, the measure of between-state discrimination was greater for mutual information. Third, discrimination based on mutual information was more robust to noise. The limitations of this study are discussed. Further comparisons should be made with frequency domain measures, with measures constructed with embedded data and with the maximal information coefficient.

We have studied the anisotropy in the in-plane resistivity and the electronic structure of isovalent Ru-substituted BaFe 2 As 2 in the antiferromagnetic-orthorhombic phase using well-annealed crystals. The anisotropy in the residual resistivity component increases in proportional to the Ru dopant concentration, as in the case of Co-doped compounds. On the other hand, both the residual resistivity and the resistivity anisotropy induced by isovalent Ru substitution is found to be one order of magnitude smaller than those induced by heterovalent Co substitution. Combined with angle-resolved photoemission spectroscopy results, which show almost the same anisotropic band structure both for the parent and Ru-substituted compounds, we confirm the scenario that the anisotropy in the residual resistivity arises from anisotropic impurity scattering in the magnetostructurally ordered phase rather than directly from the anisotropic band structure of that phase.

In Sec. III of the original paper, the carrier numbers are estimated incorrectly. The fourth paragraph of Sec. III should be replaced by "The carrier number per unit cell per spin calculated from the FS volumes of Sr122P are n α = 0.005, n β = 0.05, n γ = 0.09 (hole FSs), n δ = 0.05, and n = 0.02 (electron FSs), respectively. Although Sr122P is an isovalently substituted material, the total hole number n h = 0.15 estimated from ARPES is larger than the total electron number n e = 0.07." The present Erratum does not affect the conclusions of the original paper.

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We have investigated the superconducting gap of optimally doped Ba(Fe0.65Ru0.35)2As2 by angle-resolved photoemission spectroscopy (APRES) using bulk-sensitive 7 eV laser and synchrotron radiation. It was found that the gap is isotropic in the kx-ky plane both on the electron and hole Fermi surfaces (FSs). The gap magnitudes of two resolved hole FSs show similar kz dependences and decrease as kz approaches ~2c (i.e., around the Z point) unlike the other Fe-based superconductors reported so far, where the superconducting gap of only one hole FS shows a strong kz dependence. This unique gap structure can be understood in the scenario that the 2 orbital character is mixed into both hole FSs due to the finite spin-orbit coupling between almost degenerate FSs and is reproduced by calculations within the random phase approximation including the spin-orbit coupling.The momentum dependence of the superconducting (SC) order parameter in the Fe-based superconductors (FeSCs) has been intensively investigated by angleresolved photoemission spectroscopy (ARPES) due to their close relationship with paring mechanisms. A variety of superconducting gap symmetries in FeSCs, such as s±-wave, nodeless s++ and nodal s-wave, have been discussed from the theoretical point of view [1,2]. Up to now, even for the most intensively studied 122 systems, the situation is still complicated. As for the isovalently substituted BaFe2(As1-xPx)2 compound, it was revealed by the penetration depth and thermal conductivity measurements that there exist line nodes in the SC gap (for x = 0.33) [3]. It has been pointed out based on the random phase approximation (RPA) calculation that, three-dimensional (3D) horizontal line nodes may appear around the Z point [k = (0, 0, 2/c)] on the outermost strongly warped hole Fermi surface (FS) which has dominantly 2 orbital character [4]. However, ARPES experiments have not come to agreement on the existence of the horizontal line nodes on the 3D hole FS of BaFe2(As0.7P0.3)2 [5, 6].Ba(Fe1-xRux)2As2, another isovalently substituted system, in which doping is done at the pivotal Fe site [7,8], also exhibits a highly warped hole FS along the kz direction [9, 10]. Recent thermal conductivity measurements suggest that Ba(Fe1-xRux)2As2 has also SC gap line nodes for a wide doping range [11]. In order to clarify the SC gap structure and the location of the suggested line nodes in momentum space, we performed an ARPES study of optimally doped Ba(Fe0.65Ru0.35)2As2.In this study, two kinds of APRES apparatus were employed: one is bulk-sensitive ARPES using a vacuum ultraviolet laser; the other is based on synchrotron radiation, which allows us to trace the kz dependence of the SC gap by tuning the incident photon energy. We show that the SC gaps both on the hole FSs and electron FSs are isotropic in the kx-ky plane, while the SC gaps on the hole FSs are strongly kz dependent. Interestingly, both of the two resolved hole FSs exhibit SC gaps with almost the same kz dependence and magnitudes. We attribute this unique observat...

The isovalent-substituted iron pnictide compound SrFe2(As1−xPx)2 exhibits multiple evidence for nodal superconductivity via various experimental probes, such as the penetration depth, nuclear magnetic resonance and specific heat measurements. The direct identification of the nodal superconducting (SC) gap structure is challenging, partly because the presence of nodes is not protected by symmetry but instead caused by an accidental sign change of the order parameter, and also because of the three-dimensionality of the electronic structure. We have studied the SC gaps of SrFe2(As0.65P0.35)2 in three-dimensional momentum space by synchrotron and laser-based angle-resolved photoemission spectroscopy. The three hole Fermi surfaces (FSs) at the zone center have SC gaps with different magnitudes, whereas the SC gaps of the electron FSs at the zone corner are almost isotropic and kz-independent. As a possible nodal SC gap structure, we propose that the SC gap of the outer hole FS changes sign around the Z-X [(0, 0, 2π) − (π, π, 2π)] direction.