Transition of the near-surface δ layer in an Al/δ(Si)-GaAs tunnel structure to the insulating state under pressure

Abstract

The tunnel and lateral conductivities of an Al/GaAs tunnel structure with a surface Si δ-doped layer are measured at liquid-helium temperatures under a hydrostatic pressure of up to 3 GPa. Transition of the δ layer to the insulating state at a pressure of about 2 GPa is revealed. During this transition, the tunnel resistance increases steadily (on a logarithmic scale) and the zero-bias anomaly in the tunnel resistance exhibits a sharp peak. These results are interpreted in terms of representations of the effect of pressure on the energy-band structure and behavior of DX levels.