Hot-electron magnetophonon spectroscopy on micron- and sub-micron-size n+nn+GaAs structures

Magnetophonon resonance is used to study electronic conduction processes in a series of short n+nn+GaAs sandwich structures with active (n) layer thickness between 0.25 and 9 mu m for E up to 20 kV cm-1and B up to 18 T. The high electric fields induce a new contribution to sigmaxx, quasi-elastic inter-Landau-level scattering. The onset condition for this process can be derived from the properties of the electron eigenfunctions and eigenvalues in crossed E and B fields. A possible relation between this process and the destruction of the non-dissipative current in the quantum Hall effect is discussed. Electric-field-induced damping of the amplitudes of the magnetophonon extrema is reported and discussed in terms of the intracollisional field effect and the theory of Barker.