Luttinger-Liquid signature in scanning tunneling spectra of Li0.9Mo6O17

We present low-temperature scanning tunneling spectroscopy data from the quasi one-dimensional purple bronze Li$_{0.9}$Mo$_{6}$O$_{17}$. Our spectra show clearly a power-law behavior in density of states around Fermi-energy (-50meV $<$ E $<$ +50meV) with an exponent of $\alpha $ = 0.6 . Temperature dependent spectra between T = 5K and 50K are well-described using a model that involves tunneling into a Luttinger-Liquid at finite temperature. We do not observe any signature in the density of states near T = 24K where a insulator-to-metal transition has been reported. Finally we will discuss our data within the model of a zero bias anomaly (ZBA). However, this model does not describe the experimental data as well as the Luttinger-model does. (Oak Ridge national Laboratory, managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725)