Spin-dependent tunneling in metal-insulator-narrow gap semiconductor structures in a magnetic field

TL;DR

This study investigates spin-dependent tunneling in metal-insulator-narrow gap semiconductor structures under magnetic fields, revealing oscillations due to Landau quantization and differences in tunneling into spin sublevels influenced by surface potential.

Contribution

It provides a detailed analysis of spin-dependent tunneling oscillations and their dependence on magnetic field orientation and surface potential in narrow gap semiconductor structures.

Findings

Tunneling conductivity oscillates with magnetic field due to Landau quantization.

Amplitudes of tunneling into different spin sublevels vary significantly.

Surface potential influences the relationship between spin sublevel contributions.

Abstract

We present results of tunneling studies of p-Hg_{1-x}Cd_{x}Te-oxide-Al structures with 0.165<x<0.2 in a magnetic field up to 6 T. The tunneling 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 tunneling conductivity maxima connected with the tunneling into `a' and `b' spin sublevels are found to differ substantionally from one another, and the amplitude ratio varying from structure to structure. To understand the cause of this behavior, the tunneling 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 tunneling conductivity are dissimilar and the relationship between them depends strongly on the value of surface potential.