ON LOCAL AND GLOBAL CURRENTS IN MESOSCOPIC CONDUCTORS

Using linear response theory we show that, in a quasi-stationary state , the local multiprobe conductance of a mesoscopic system of non-inter acting electrons with a time reversal invariant Hamiltonian does not d epend on the local shape of the driving self-consistent potential and thus is entirely determined by the asymptotic values of the potential in the leads. In the ballistic limit, the local conductance in the lat eral direction exhibits oscillations depending on the occupation of ch annels. Scattering by a point impurity leads to softening of the quant ized global conductance steps. In addition to that for an attractive s cattering potential, a dip occurs in each plateau regime the shape of which is calculated for different values of the potential strength. We also investigate the local conductance for both a point scatterer and a finite scattering region.