Magnetic-field-dependent Zero-bias Diffusive Anomaly in Pb oxide– n-InAs Structures: Coexistence of Two- and Three-dimensional States

Abstract

The results of experimental and theoretical studies of zero-bias anomaly (ZBA) in the Pb-oxide-(Formula presented)-InAs tunnel structures in magnetic field up to 6 T are presented. A specific feature of the structures is a coexistence of the two-dimensional (2D) and 3D states at the Fermi energy near the semiconductor surface. The dependence of the measured ZBA amplitude on the strength and orientation of the applied magnetic field is in agreement with the proposed theoretical model. According to this model, electrons tunnel into 2D states, and move diffusively in the 2D layer, whereas the main contribution to the screening comes from 3D electrons. © 1999 The American Physical Society.