Fermi surface and electronic structure of incommensurate charge-density wave systems

We study the single-particle spectra of a model that shows an incommensurat e charge-density wave (CDW) instability arising from the competition betwee n phase separation and long-range Coulomb interactions. Starting from an op en Fermi surface, we find that the resulting CDW is oriented along the (1, 0) and (or) (0, 1) direction, which allows for a purely one-dimensional (1D ) or a two-dimensional (2D) eggbox type charge modulation. In both cases, t he van Hove singularities are substantially enhanced, and the spectral weig ht of Fermi surface states near the M points tends to be suppressed. Remark ably, a leading edge gap arises near these point, which, in the eggbox case , leaves finite arcs of the Fermi surface gapless.