Observation of ballistic holes

We report the first direct observation of ballistic hole transport in semiconductors, via energy spectroscopy experiments. Light holes are preselected and injected via tunneling into 31-nm-thick ${\mathrm{p}}^{+}$ GaAs layers. About 10% of the injected holes have been found to travel ballistically maintaining distributions ≃35 meV wide, with a mean free path of about 14 nm. Resonances in the injection currents, resulting from quantum interference effects of the ballistic holes, are used to support the light nature of the ballistic holes.