The Effect of a Surface Potential on Spin-Dependent Tunnelling in Metal-Insulator Narrow-gap Semiconductor Structures in a Magnetic Field

Abstract

We present results of tunnelling studies of p-Hg1-xCdxTe-oxide-Al structures with 0.165 < x < 0.2 in a magnetic field up to 6 T. The tunnelling conductivity oscillations resulting from the Landau quantization of the energy spectrum in the semiconductor volume are investigated. under an in-plane magnetic field the amplitudes of tunnelling conductivity maxima connected with the tunnelling into a and b spin sublevels are found to differ substantially from one another, and the amplitude ratio varies from structure to structure. To understand the cause of this behaviour, the tunnelling conductivity for this magnetic field orientation is calculated taking into consideration the multi-band energy spectrum. It is shown that the contributions of the different spin sublevels to the tunnelling conductivity are dissimilar and the relationship between them depends strongly on the value of surface potential.