Imaging of cyclotron emission from edge channels in quantum hall conductors

A local probing technique of cyclotron emission is applied to image nonequilibrium electrons generated along edge channels in quantum Hall conductors. In a lower-magnetic field region of a quantum Hall state plateau (filling factor 2<nu), cyclotron emission is found to occur along the boundary of a conductor on the side of lower potential (with positive Hall voltage). The emission indicates that electrons are accumulated in the first-excited Landau level, while they are depleted in the lowest Landau level along the boundary as a consequence of adiabatic-transport.