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The ordered (1 x 2) monolayer of Bi on the InAs(110) surface is studied by means of angle-resolved high-resolution ultra-violet photoemission at room temperature. Four bands of Bi;induced surface states are singled out and their dispersion is mapped along the high-symmetry directions of the surface Brillouin zone. The highest occupied state S' lies inside the InAs(110) energy gap at 0.2 eV binding energy and spreads across the Fermi level, determining the semimetallic character of the system. The second-highest occupied state Sn is located at 0.83 eV binding energy (at ), while states Sm and SN are located near the internal gap edge at 2.57 eV and 3.3 eV binding energy, and present band dispersions along (X) over bar of similar to 340 meV and 300 meV, respectively. The Pi-induced bands of the (1 x 2) phase are shifted in energy relative to the corresponding bands of the (1 x 1)-Bi/InAs(110) phase and their width is reduced. These differences are discussed in the light of the geometric structure of the two phases.

The authors have performed a high-energy-resolution photoelectron spectroscopy investigation of the quasi-two-dimensional material 2H-TaSe2. Temperature-dependent constant-binding energy curves reveal that characteristic changes in the electronic density of states occur continuously through the second-order charge-density-wave (CDW) transition at 122 K. The photoelectron spectra indicate that different parts of the Fermi surface are unequally affected by the CDW and suggest the formation of an energy gap in the Gamma K direction of the Brillouin zone.

The authors have studied experimentally and theoretically the effect of the core hole on the local density of both occupied and unoccupied states at a core ionised Al site in AlNi. They compare calculated local Al p and s state densities with experimental data for X-ray emission (XES), Auger (AES) and X-ray absorption (XAS) spectroscopy, which reflect the local DOS in the absence (KV and LV XES) and in the presence (KLV Auger and XAS) of a core hole. From this comparison they conclude that core hole effects are appreciable, although their precise determination is hindered by self-energy effects in this particular system. These results suggest that interpretation of the K-edge X-ray absorption spectra of light elements like Al in alloys and compounds in terms of one-particle groundstate DOS is in general inappropriate.