Affiliation
QuTech
A hole bilayer in a strained germanium double quantum well is designed, fabricated, and studied. Magnetotransport characterization of double quantum well field-effect transistors as a function of gate voltage reveals the population of two hole channels with a high combined mobility and a low percolation density. The individual population of the channels from the interference patterns of the Landau fan diagram was resolved. When the system is in resonance an anti-crossing of the first two bilayer subbands is observed and a symmetric-antisymmetric gap of ≈0.69meV is estimated, in agreement with Schrödinger-Poisson simulations.