Bo Zhou

Electronic structure of Fe1.04Te0.66Se0.34

We report the electronic structure of the iron-chalcogenide superconductor, Fe-1.04(Te0.66Se0.34), obtained with high-resolution angle-resolved photoemission spectroscopy and density-functional calculations. In photoemission measurements, various photon e

Doping-insensitive density-of-states suppression in polycrystalline iron-based superconductor SmO1−xFxFeAs

Abstract We investigated the temperature dependence of the density-of-states in the iron-based superconductor SmO 1− x F x FeAsxa0( x =0,0.12,0.15,0.2) with high resolution angle-integrated photoemission spectroscopy. The density-of-states suppression is observed with decreasing temperature in all samples, revealing two characteristic energy scales (10xa0meV and 80xa0meV). However, no obvious doping dependence is observed. We argue that the 10xa0meV suppression is due to an anomalously doping-independent normal state pseudogap, which becomes the superconducting gap once in the superconducting state; and alert the possibility that the 80xa0meV-scale suppression might be an artifact of the polycrystalline samples.

High-resolution angle-resolved photoemission spectroscopy study of the electronic structure of EuFe 2 As 2

We report the high-resolution angle-resolved photoemission spectroscopy studies of electronic structure of EuFe2As2. The paramagnetic state data are found to be consistent with density-functional calculations. In the antiferromagnetic ordering state of Fe, our results show that the band splitting, folding, and hybridization evolve with temperature, which cannot be explained by a simple folding picture. Detailed measurements reveal that a tiny electron Fermi pocket and a tiny hole pocket are formed near (pi,pi) in the (0,0)-(pi,pi) direction, which qualitatively agree with the results of quantum oscillations, considering kz variation of Fermi surface. Furthermore, no noticeable change within the energy resolution is observed across the antiferromagnetic transition of Eu2+ ordering, suggesting weak coupling between Eu sublattice and FeAs sublattice.

High-resolution angle-resolved photoemission spectroscopy study of the electronic structure of EuFe2As2

We report the high-resolution angle-resolved photoemission spectroscopy studies of electronic structure of EuFe2As2. The paramagnetic state data are found to be consistent with density-functional calculations. In the antiferromagnetic ordering state of Fe, our results show that the band splitting, folding, and hybridization evolve with temperature, which cannot be explained by a simple folding picture. Detailed measurements reveal that a tiny electron Fermi pocket and a tiny hole pocket are formed near (pi,pi) in the (0,0)-(pi,pi) direction, which qualitatively agree with the results of quantum oscillations, considering kz variation of Fermi surface. Furthermore, no noticeable change within the energy resolution is observed across the antiferromagnetic transition of Eu2+ ordering, suggesting weak coupling between Eu sublattice and FeAs sublattice.

Electronic structure of BaNi2As2

BaNi2As2, with a first-order phase transition around 131 K, is studied by the angle-resolved photoemission spectroscopy. The measured electronic structure is compared to the local-density approximation calculations, revealing similar large electronlike bands around (M) over bar and differences along (T) over bar-(X) over bar. We further show that the electronic structure of BaNi2As2 is distinct from that of the sibling iron pnictides. Particularly, there is no signature of band folding, indicating no collinear spin-density-wave-related magnetic ordering. Moreover, across the strong first-order phase transition, the band shift exhibits a hysteresis, which is directly related to the significant lattice distortion in BaNi2As2.

Electronic structure ofBaNi2As2

BaNi2As2, with a first-order phase transition around 131 K, is studied by the angle-resolved photoemission spectroscopy. The measured electronic structure is compared to the local-density approximation calculations, revealing similar large electronlike bands around (M) over bar and differences along (T) over bar-(X) over bar. We further show that the electronic structure of BaNi2As2 is distinct from that of the sibling iron pnictides. Particularly, there is no signature of band folding, indicating no collinear spin-density-wave-related magnetic ordering. Moreover, across the strong first-order phase transition, the band shift exhibits a hysteresis, which is directly related to the significant lattice distortion in BaNi2As2.

High-resolution angle-resolved photoemission spectroscopy study of the electronic structure ofEuFe2As2

We report the high-resolution angle-resolved photoemission spectroscopy studies of electronic structure of EuFe2As2. The paramagnetic state data are found to be consistent with density-functional calculations. In the antiferromagnetic ordering state of Fe, our results show that the band splitting, folding, and hybridization evolve with temperature, which cannot be explained by a simple folding picture. Detailed measurements reveal that a tiny electron Fermi pocket and a tiny hole pocket are formed near (pi,pi) in the (0,0)-(pi,pi) direction, which qualitatively agree with the results of quantum oscillations, considering kz variation of Fermi surface. Furthermore, no noticeable change within the energy resolution is observed across the antiferromagnetic transition of Eu2+ ordering, suggesting weak coupling between Eu sublattice and FeAs sublattice.

Electronic structure of BaNi

BaNi2As2, with a first-order phase transition around 131 K, is studied by the angle-resolved photoemission spectroscopy. The measured electronic structure is compared to the local-density approximation calculations, revealing similar large electronlike bands around (M) over bar and differences along (T) over bar-(X) over bar. We further show that the electronic structure of BaNi2As2 is distinct from that of the sibling iron pnictides. Particularly, there is no signature of band folding, indicating no collinear spin-density-wave-related magnetic ordering. Moreover, across the strong first-order phase transition, the band shift exhibits a hysteresis, which is directly related to the significant lattice distortion in BaNi2As2.