Quantization effects in the conductance of metallic contacts at room temperature

We present measurements on conductance quantization in atomic scale metallic constrictions at room temperature. Conductance measurements as a function of constriction size reveal pronounced horizontal plateaus separated by sharp discrete steps. Most individual conductance plateaus are close to integer multiples of the fundamental conductance unit but definite deviations are also present. After averaging over many contact configurations, conductance quantization is seen clearly and more prominently than in similar recent low temperature measurements on the same metals.