Observation of a node in the quantum oscillations induced by microwave radiation

The microwave induced magnetoresistance in a GaAs/AlGaAs heterostructure was studied at temperatures below 1 K and frequencies in the range of 150–400 GHz. A distinct node in the Shubnikov–de Haas oscillations, induced by the microwave radiation, is clearly observed. The node position coincides with the position of the cyclotron resonance on the carriers with effective mass (0.068±0.005)m0.