Band-Structure Effects in Metal-GaSb Tunnel Contacts Under Pressure

Tunneling at 4.2°K from lead into degenerate $n$-type GaSb under hydrostatic pressure exhibits huge changes when conduction-band extrema cross each other. In the indirect-gap configuration, strong phonon-assisted structures show up together with a typical resistance kink related to the onset of a (000) tunneling path. The measured interband pressure coefficient is -9.6 meV/kbar. All results suggest that the band crossing occurs 3 kbar higher than expected.