High-resolution photoemission spectroscopy of CeSi single crystal

We have investigated the valence-band electronic structures for a CeSi sing le crystal using high-resolution ultraviolet photoemission spectroscopy at 7 and 290 K. The spectra do not show a so-called tail of Kondo resonance ev en at 7 K. This indicates that the Kondo effect is very weak in CeSi, that is, the Kondo temperature is very low. In comparing the spectrum measured a t 7 K with that at 290 K, the spectral intensity at 7 K near the Fermi edge decreases and that in the energy range 20-100 meV increases. The redistrib ution of the spectral intensity is related to the formation of magnetic ord ering in CeSi at low temperature. (C) 2001 Elsevier Science B.V. All rights reserved.