Resistance resonance induced by electron-hole hybridization in a strongly coupled InAs/GaSb/AlSb heterostructure

We observe large resistance increases in a crossed band-gap electron-hole system owing to a coupling-induced energy gap at the point of anticrossing between the electron and hole dispersion relations. Samples with various degrees of coupling have been fabricated with front and back gates, which are able to deplete completely the electrons or holes, respectively. This has enabled a systematic study of the electron-hole coupling as a function of the total charge in the system. These results are interpreted in the light of recent theoretical predictions about two-dimensional electron-hole systems and equivalent experimental work on strongly coupled double two-dimensional electron gases. The temperature dependence of the coupling-induced resistance enhancement of the material has also been investigated, allowing us to obtain the magnitude of the resultant energy gap in the dispersion relations, which is found to be approximately 2 meV in the sample with the strongest coupling.