POSSIBLE OBSERVATION OF A LUTTINGER-LIQUID BEHAVIOR FROM PHOTOEMISSION SPECTROSCOPY OF ONE-DIMENSIONAL ORGANIC CONDUCTORS

High-resolution photoemission experiments have been carried out on one-dimensional organic conductors in their normal state. In contrast to usual metals, the spectral function vanishes at the Fermi level and no Fermi edge is detectable. These results are consistent with a Luttinger description and an exponent alpha of the spectral function at the Fermi level larger than 1 is found. This result corroborates recent nuclear-magnetic-resonance experiments. Such a large correlation exponent shows that the 1D Hubbard model is not appropriate and strong long-range interactions must be assumed to play an important role in these materials. The compatibility with other correlation functions is discussed.