Coulomb charging effects in an open quantum dot device at zero magnetic field

We report low-temperature conductance measurements of an open quantum dot d evice formed in a clean one-dimensional (1D) channel. At zero magnetic fiel d. continuous and periodic oscillations superimposed upon ID ballistic cond uctance steps are observed. We ascribe the observed conductance oscillation s when the conductance through the dot G exceeds 2e(2)/h, to experimental e vidence for Coulomb charging effects in an open dot. This is supported by t he evolution of the oscillating features for G > 2e(2)/h as a function of b oth temperature and barrier transparency.