Tunneling between dilute GaAs hole layers

We report interlayer tunneling measurements between very dilute two-dimensional GaAs hole layers. Surprisingly, the shape and temperature dependence of the tunneling spectrum can be explained with a Fermi liquid-based tunneling model, but the peak amplitude is much larger than expected from the available hole band parameters. Data as a function of parallel magnetic field reveal additional anomalous features, including a recurrence of a zero-bias tunneling peak at very large fields. In a perpendicular magnetic field, we observe a robust and narrow tunneling peak at total filling factor νT=1, signaling the formation of a bilayer quantum Hall ferromagnet.