Angle-resolved photoemission study of K_0.3MoO₃: Direct observation of temperature-dependent Fermi surface across the Peierls transition

The temperature dependence of the low-energy electronic state for a typical quasi-one-dimensional material K_0.3MoO₃ has been investigated using high-resolution angle-resolved photoemission spectroscopy. We observed well-defined open quasi-one-dimensional Fermi surfaces (FSs) throughout the entire Brillouin zone. The warping of the FSs arising from the finite interchain transfer is also clearly discernible; this seems to be reduced at low temperature. It is indicative of the variation of the nesting condition, from imperfect to nearly perfect, on decreasing the temperature across the Peierls transition.