MAGNETIC-FIELD EFFECTS ON SWITCHING NOISE IN A QUANTUM POINT CONTACT

[摘要] We extend a previous study of the quantum-size effect on switching noise in a GaAs/AlxGa1-xAs quantum point contact in zero magnetic field to the quantum Hall regime. The experimental results agree well with a model based on temporal electrostatic fluctuations of the conduction-band bottom in the point contact. A confirmation of our interpretation is obtained by a direct comparison of the noise data with measurements of the transconductance. The analysis of the data suggests that the Lande g factor in a quantum point contact is enhanced with respect to the low bare g factor of GaAs.

[关键词] ELECTRON-GAS;RESISTANCE;TRANSPORT