Corrections to the one-dimensional density of states: Observation of a Coulomb gap?

Abstract

We report the first systematic study of the corrections to the electron density of states of a 1D system, ultranarrow granular aluminum wires. These corrections do not have the ${\mathrm{V}}^{\mathrm{-}1/2}$ dependence predicted by theory, but are significantly larger than the corrections observed in corresponding bulk samples. At high magnetic fields, low temperatures, and very low voltages, we see evidence of a logarithmic gap in the density of states.