CURRENT-DENSITY IN A QUANTUM HALL BAR

When current is forced through a quantum Hall bar it is understood tha t it flows primarily through edge states. These represent extra charge s that in turn produce a more widely distributed current density that falls off rather slowly with distance and then drops rapidly as a resu lt of screening by particles beyond the depletion region. We have solv ed numerically the self-consistent Schrodinger equation in the Hartree approximation for ideal samples with small widths and sharp boundarie s, and combined these results with the Wiener-Hopf technique to obtain an accurate picture of the situation for macroscopically wide samples . Our results indicate that the redistribution of states in the bulk o f a quantum Hall bar is a very important effect and that the bulk stat es contribute to a significant fraction of the total current.