We experimentally study the phase diagram of the integer quantized Hall effect, as a function of density and magnetic field. We used a two dimensional hole system confined in a Ge/SiGe quantum well, where all energy levels are resolved, because the Zeeman splitting is comparable to the cyclotron energy. At low fields and close to the quantum Hall liquid-to-insulator transition, we observe the floating up of the lowest energy level, but NO FLOATING of any higher levels, rather a merging of these levels into the insulating state. For a given filling factor, only direct transitions between the insulating phase and higher quantum Hall liquids are observed as a function of density. Finally, we observe a peak in the critical resistivity around filling factor one.
@article{arxiv.cond-mat/9906212,
title = {Phase diagram of the integer quantum Hall effect in p-type Germanium},
author = {M. Hilke and D. Shahar and S. H. Song and D. C. Tsui and Y. H. Xie},
journal= {arXiv preprint arXiv:cond-mat/9906212},
year = {2009}
}