One-dimensional ballistic channel with a triple-barrier longitudinal potential: Measurement and model

Low-temperature measurements of the conductance of a long one-dimensional ballistic constriction with a narrow-wide-narrow-wide-narrow geometry are presented. The results are compared with a numerical calculation of the transmission probability for the longitudinal potential estimated from the lithographic dimensions, the carrier concentration, and the depth of the unpatterned two-dimensional electron gas. We find good agreement between measurement and this very simple model for particular gate-voltage conditions and when there is only one occupied one-dimensional subband. We suggest that there is electron phase coherence along the whole device at the measurement temperature of 35 mK.