Total Angular Momentum Conservation During Tunnelling through Semiconductor Barriers

TL;DR

This paper demonstrates the conservation of total angular momentum during resonant tunnelling in semiconductor heterostructures, revealing that heavy hole states dominate tunnelling processes while light hole states do not contribute to the first resonance.

Contribution

It provides the first experimental evidence of total angular momentum conservation in valence band resonant tunnelling through semiconductor barriers.

Findings

Heavy hole levels dominate tunnelling resonances.

No tunnelling through the first light hole state observed.

Conservation of total angular momentum confirmed.

Abstract

We have investigated the electrical transport through strained p-Si/Si_{1-x}Ge_x double-barrier resonant tunnelling diodes. The confinement shift for diodes with different well width, the shift due to a central potential spike in a well, and magnetotunnelling spectroscopy demonstrate that the first two resonances are due to tunnelling through heavy hole levels, whereas there is no sign of tunnelling through the first light hole state. This demonstrates for the first time the conservation of the total angular momentum in valence band resonant tunnelling. It is also shown that conduction through light hole states is possible in many structures due to tunnelling of carriers from bulk emitter states.