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

Abstract

Angle-resolved photoemission spectroscopy of $\mathrm{Zr}{\mathrm{Te}}_{3}$ has been performed from room temperature $(T)$ down to $6\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ (across ${T}_{\mathrm{CDW}}=63\phantom{\rule{0.3em}{0ex}}\mathrm{K}$) 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 ${T}_{\mathrm{CDW}}$. 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.