K. Kanai

Temperature-dependent Luttinger surfaces.

The Luttinger surface of an organic metal (TTF-TCNQ), possessing charge order and spin-charge separated band dispersions, is investigated using temperature-dependent angle-resolved photoemission spectroscopy. The Luttinger surface topology, obtained from momentum distribution curves, changes from quasi-2D (dimensional) to quasi-1D with temperature. The high temperature quasi-2D surface exhibits 4kF charge-density-wave (CDW) superstructure in the TCNQ derived holon band, in the absence of 2kF order. Decreasing temperature results in quasi-1D nested 2kF CDW order in the TCNQ spinon band and in the TTF surface. The results establish the link in momentum space between charge order and spin-charge separation in a Luttinger liquid.

Ultrahigh-resolution and angle-resolved photoemission study of SmB6

Abstract The photoemission spectra with the ultrahigh-energy resolution reveal the small gap formation at lower temperatures than the characteristic coherent temperature T coh . In addition, the temperature dependence of the density of states at Fermi level clearly shows a simple scaling relationship with T coh . The narrow 4f-band with a very small dispersion just below E F are observed by angle-resolved spectra at the first time.

Temperature dependence study of inverse photoemission spectra at Ce 4d absorption edge of CePd3

Abstract A resonant inverse photoemission study (RIPES) at Ce 4 d →4 f absorption edge of CePd 3 has been carried out. The excitation energy dependence of 4 f spectral resonance indicates 4 d –4 f multiplet splitting in the intermediate state of the RIPES process. Asymmetric constant final state spectra (CFS) show Fano-type line shape in contrast to the 3 d –4 f RIPES. A clear temperature dependence of 4 f structures near Fermi level is observed in the RIPES spectra. This fact indicates the process of the low lying excited state starting to be occupied and the 4 f electron localizing as temperature increases, which is consistent with the NCA calculation. It is found, however, that the 4 f electron still shows strong itinerant character at a temperature around Kondo temperature.

Resonant inverse photoemission study on strongly correlated systems

Abstract We have performed resonant inverse photoemission (RIPE) spectroscopy on the transition metal and rare-earth metal compounds in the ultraviolet energy region. We present, here, some characteristics of the RIPE spectra of several intermetallic Ce compounds at the Ce-N 4,5 absorption edge. Clear RIPE spectra are observed. From the comparison between the experimental and the calculated spectra, the resonance behaviors can be well explained within the localized picture of the 4f electrons. On the other hand, the information about the fractional 4f occupancy in the systems with high Kondo temperature is strongly reflected in the intensities of the coherent and incoherent components of RIPE spectra. The RIPE spectra sensitively detect the variations in the 4f electronic states by destruction of the collective Kondo state, with increasing temperature. We can derive direct information about the temperature and T K dependence of the 4f electronic states from the spectra. On the other hand, it is necessary to take the surface contributions into account in order to derive quantitative information. We present an example of the analysis of RIPE spectra at N 4,5 pre-threshold, including both contributions from the bulk and surface.

Conduction band satellite of Ni metal observed using 3p-3d resonant inverse photoemission study

Resonant inverse photoemission spectra of Ni metal have been obtained across the Ni 3

Ultrahigh-resolution photoemission and resonant-inverse photoemission spectroscopy on CePd3

p

Resonant inverse photoemission study of CeCoGe3−xSix

absorption edge. The intensity of Ni 3

High-energy spectroscopy of NaV2O5

d

Photoemission spectroscopic evidence of gap anisotropy in an f-electron superconductor.

band just above Fermi edge shows asymmetric Fano-like resonance. Satellite structures are found at about 2.5 and 4.2 eV above Fermi edge, which show resonant enhancement at the absorption edge. The satellite structures are due to a many-body configuration interaction and confirms the existence of 3

Ultrahigh-resolution photoemission spectroscopy of superconductors using a VUV laser

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