A. Fujimori

Distinct Fermi-momentum dependent energy gaps in deeply underdoped Bi2212.

We used angle-resolved photoemission spectroscopy applied to deeply underdoped cuprate superconductors Bi2Sr2Ca(1–x)YxCu2O8 (Bi2212) to reveal the presence of two distinct energy gaps exhibiting different doping dependence. One gap, associated with the antinodal region where no coherent peak is observed, increased with underdoping, a behavior known for more than a decade and considered as the general gap behavior in the underdoped regime. The other gap, associated with the near-nodal regime where a coherent peak in the spectrum can be observed, did not increase with less doping, a behavior not previously observed in the single particle spectra. We propose a two-gap scenario in momentum space that is consistent with other experiments and may contain important information on the mechanism of high–transition temperature superconductivity.

Characterization of magnetic components in the diluted magnetic semiconductor Zn1-xCoxO by x-ray magnetic circular dichroism

We report on the results of x-ray absorption (XAS), x-ray magnetic circular dichroism (XMCD), and photoemission experiments on {\it n}-type Zn

Electronic structure of La2-xSrxCuO4 in the vicinity of the superconductor-insulator transition

_{1-x}

Doping dependent density of states and pseudogap behavior in La2-xSrxCuO4

Co

Low-energy electronic structure of the high-Tc cuprates La2−xSrxCuO4 studied by angle-resolved photoemission spectroscopy

_x

Thickness-dependent electronic structure of ultrathin SrRuO3 films studied by in situ photoemission spectroscopy

O (

Metal ordering and oxygen displacements in (Nd, Sr, Ce)2CuO4 − y

x=0.05

Multiple bosonic mode coupling in the electron self-energy of (La2-xSrx)CuO4

) thin film, which shows ferromagnetism at room temperature. The XMCD spectra show a multiplet structure, characteristic of the Co

Dual nature of the electronic structure of (La2-x-yNdySrx)CuO4 and La1.85Sr0.15CuO4

^{2+}

Orbital ordering in La0.5Sr1.5MnO4 studied by soft x-ray linear dichroism

ion tetrahedrally coordinated by oxygen, suggesting that the ferromagnetism comes from Co ions substituting the Zn site in ZnO. The magnetic field and temperature dependences of the XMCD spectra imply that the non-ferromagnetic Co ions are strongly coupled antiferromagnetically with each other.