Role of charge-density-wave fluctuations on the spectral function in a metallic charge-density-wave system

Angle-resolved photoemission spectroscopy of Zr Te3 has been performed from room temperature (T) down to 6 K (across TCDW =63 K) to study the charge-density-wave (CDW) fluctuation effects in a metallic CDW compound having Fermi surface (FS) sheets with differing dimensionality. While spectra on the three-dimensional (3D) FS show typical Fermi-Dirac functionlike T dependence, those along the quasi-one-dimensional (1D) FS show formation of a pseudogap, starting at a much higher T than TCDW. Simultaneously, a van-Hove singularity consisting of the quasi-1D FS intersecting the 3D FS shows an increase of coherence. This demonstrates the role of CDW fluctuations on the spectral function, and relation to the dimensionality of the states, in a metallic CDW system.