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High quality In2O3 single crystals of bcc structure were grown by chemical vapour transport. The temperature dependence of resistivity, Hall constant, and mobility yielded an electron density of n = 1.3 × 1019 cm−3. The transport properties showed characteristics best describable by the degenerate semiconductor model. The crystals were additionally investigated by high resolution angular resolved photoelectron spectroscopy (ARPES). Emission from the valence band and the partially filled conduction band at the Γ point yielded a direct bandgap of (2.7 ± 0.1)eV. The partially filled conduction band furthermore enabled the determination of its three dimensional Fermi surface and the effective masses m* by ARPES.

PACS. 78.47.+p -Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter. PACS. 74.72.-h -High-Tc compounds. PACS. 74.76.Bz -High-Tc films.Abstract. -Using a femtosecond pump-probe optical technique, we measured the time-resolved change in reflectivity of three single-layer cuprate samples, including Bi2Sr2−xLaxCuO6+z, La2CuO4+y and La2−xSrxCuO4 grown on SrTiO3. We analyze the data in terms of a nonthermal electron relaxation model, and obtain quantitative agreement between the model and the data. The initial electron-electron thermalization process is much longer in the superconducting samples as opposed to the overdoped nonsuperconducting sample, suggesting a bottleneck in electron thermalization process due to the presence of the superconducting gap.c EDP Sciences

Bi 2 Sr 2-x La x CuO 6+δ and Bi 2-y Pb y Sr 2-x La x CuO 6+δ high-T c superconductors in a wide doping range from overdoped to heavily underdoped were studied by x-ray absorption and photoemission spectroscopy. The hole concentration p was determined by an analysis of the Cu L 3 -absorption edge. Besides the occupied density of states derived from photoemission, the unoccupied density of states was determined from the prepeak of the O K-absorption edge. Both, the occupied as well as the unoccupied density of states reveal the same dependence on hole doping, i.e. a continuous increase with increasing doping in the hole underdoped region and a constant density in the hole overdoped region. By comparing these results of single-layer BSLCO with previous results on single-layer LSCO it could be argued that besides the localized holes on Cu sites the CuO 2 -planes consist of two types of doped holes, from which the so-called mobile holes determine the intensity of the prepeak of the O 1s absorption edge

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