Electronic structure near the Fermi surface in the quasi-one-dimensional conductor Li0.9Mo6O17

The electronic properties of the quasi-one-dimensional (1D) oxide conductor Li0.9Mo6O17 have been investigated using high-momentum and energy resoluti on photoelectron spectroscopy at temperatures above and below the metal-sem iconductor transition temperature. Considerable spectral intensity at the F ermi energy (E-F) is observed at room temperature, and a sharp feature corr esponding to a band crossing E-F is clearly resolved for states along the q uasi-1D axis. Below the metal-semiconductor transition at 24 K, a gap is cl early observed to open at E-F. Our data do not support the assertion that t he low energy excitations of electrons in Li0.9Mo6O17 should be described i n a Luttinger liquid model.