JETP Letters: issues online

$The differential tunneling resistance R and the tunneling spectra Rd2I/dV2 of n-GaAs/Au junctions have been studied as a fun ction of the magnetic field В in longitudinal (B\\l) and transverse (B1I) fields up to 23 Τ at 4.2 K. A quantizing magnetic field alters the various R(V) curves in a similar way. It leaves the tunneling spectra essentially unchanged, except at bias voltages V at which there are manifestations of many-particle effects in the tunneling: an anomaly at a zero voltage and phonon features in the tunneling spectra. These results suggest that the behavior of Я as a function of V and В can be described by the multiplicative expression R*-f(V)g(B) within contributions of many-particle interactions (an exchange-correlation interaction and a polaron interaction). Expressions are derived for the behavior R(B) at V=0. Theoretical curves are compared with experimental data. The discrepancies found indicate that it is necessary to consider the change caused in the shape of the self-consistent Schottky barrier by the effect of the quantizing magnetic field on screening. In the case of a longitudinal field, the only possible cause of a magnetoresistance of tunnel junctions would be Landau quantization of the spectrum of free carriers. A comparison of the R curves with Shubnikov-de Haas oscillations of the bulk resistivity of n-GaAs indicates that scattering processes which suppress magnetic quantization in the interior of the semiconductor, when the condition wct^1 does not hold, do not prevent quantization of electrons near the Schottky barrier in far weaker fields.$

The differential tunneling resistance R and the tunneling spectra Rd²I/dV² of n-GaAs/Au junctions have been studied as a fun ction of the magnetic field В in longitudinal (B\\l) and transverse (B1I) fields up to 23 Τ at 4.2 K. A quantizing magnetic field alters the various R(V) curves in a similar way. It leaves the tunneling spectra essentially unchanged, except at bias voltages V at which there are manifestations of many-particle effects in the tunneling: an anomaly at a zero voltage and phonon features in the tunneling spectra. These results suggest that the behavior of Я as a function of V and В can be described by the multiplicative expression R*-f(V)g(B) within contributions of many-particle interactions (an exchange-correlation interaction and a polaron interaction). Expressions are derived for the behavior R(B) at V=0. Theoretical curves are compared with experimental data. The discrepancies found indicate that it is necessary to consider the change caused in the shape of the self-consistent Schottky barrier by the effect of the quantizing magnetic field on screening. In the case of a longitudinal field, the only possible cause of a magnetoresistance of tunnel junctions would be Landau quantization of the spectrum of free carriers. A comparison of the R curves with Shubnikov-de Haas oscillations of the bulk resistivity of n-GaAs indicates that scattering processes which suppress magnetic quantization in the interior of the semiconductor, when the condition w_ct^1 does not hold, do not prevent quantization of electrons near the Schottky barrier in far weaker fields.