Abstract
We have characterized the electronic properties of a high-mobility two-dimensional electron system in modulation doped InAsSb quantum wells and compare them to InSb quantum wells grown in a similar fashion. Using temperature-dependent Shubnikov-de Haas experiments as well as FIR transmission we find an effective mass of m^∗ ≈ 0.022m_e, which is lower than in the investigated InSb quantum well, but due to a rather strong confinement still higher than in the corresponding bulk compound. The effective g-factor was determined to be g^∗ ≈ 21.9. These results are also corroborated by k · p band structure calculations. When spin polarizing the electrons in a tilted magnetic field, the g-factor is significantly enhanced by electron-electron interactions, reaching a value as large as g^∗ = 60 at a spin polarization P = 0.75. Finally, we show that due to the low effective mass the quantum Hall effect in our particular sample can be observed up to a temperature of 60 K and we propose scenarios how to increase this temperature even further.