J. Geck

Orbital polaron lattice formation in lightly doped La1-xSrxMnO3

By resonant x-ray scattering at the Mn K edge on La(7/8)Sr(1/8)MnO3, we show that an orbital polaron lattice (OPL) develops at the metal-insulator transition of this compound. This orbital reordering explains consistently the unexpected coexistence of ferromagnetic and insulating properties at low temperatures, the quadrupling of the lattice structure parallel to the MnO2 planes, and the observed polarization and azimuthal dependencies. The OPL is a clear manifestation of strong orbital-hole interactions, which play a crucial role for the colossal magnetoresistance effect and the doped manganites in general.

Observation of electronic ferroelectric polarization in multiferroic YMn2O5.

We report the observation of a magnetic polarization of the O 2p states in YMn(2)O(5) through the use of soft x-ray resonant scattering at the oxygen K edge. Remarkably, we find that the temperature dependence of the integrated intensity of this signal closely follows the macroscopic electric polarization, and hence is proportional to the ferroelectric order parameter. This is in contrast with the temperature dependence observed at the Mn L(3) edge, which reflects the Mn magnetic order parameter. First-principles calculations provide a microscopic understanding of these results and show that a spin-dependent hybridization of O 2p and Mn 3d states results in a purely electronic contribution to the ferroelectric polarization, which can exist in the absence of lattice distortions.

Relation between the one-particle spectral function and dynamic spin susceptibility of superconducting Bi2Sr2CaCu2O8-δ

Angle resolved photoemission spectroscopy (ARPES) provides a detailed view of the renormalized band structure and, consequently, is a key to the self-energy and the single-particle Greens function. Here we summarize the ARPES data accumulated over the whole Brillouin zone for the optimally doped Bi

Pressure dependence of the charge density wave in 1T-TaS2 and its relation to superconductivity

_2

Electronic structure of CeCoIn 5 from angle-resolved photoemission spectroscopy

Sr

Momentum and temperature dependence of renormalization effects in the high-temperature superconductor YBa2Cu3O7- δ

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X-ray absorption spectroscopy of Na x Co O 2 layered cobaltates

CaCu

Reevaluation of the coupling to a bosonic mode of the charge carriers in (Bi,Pb)2Sr2CaCu2O8+δ at the antinodal point

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Unidirectional diagonal order and three-dimensional stacking of charge stripes in orthorhombic Pr1.67Sr0.33NiO4 and Nd1.67Sr0.33NiO4

O

Electronic confinement and ordering instabilities in colossal magnetoresistive bilayer manganites.

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