title: Fractional Quantum Hall States in a Ge Quantum Well.
abstract: Measurements of the Hall and dissipative conductivity of a strained Ge quantum well on a SiGe/(001)Si substrate in the quantum Hall regime are reported. We analyze the results in terms of thermally activated quantum tunneling of carriers from one internal edge state to another across saddle points in the long-range impurity potential. This shows that the gaps for different filling fractions closely follow the dependence predicted by theory. We also find that the estimates of the separation of the edge states at the saddle are in line with the expectations of an electrostatic model in the lowest spin-polarized Landau level (LL), but not in the spin-reversed LL where the density of quasiparticle states is not high enough to accommodate the carriers required.
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom and International Laboratory of High Magnetic Fields and Low Temperatures, 95 Gajowicka Street, 53-421 Wroclaw, Poland.
authors.forename: O A
authors.initials: OA
authors.lastname: Mironov
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: N
authors.initials: N
authors.lastname: d'Ambrumenil
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Dobbie
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: D R
authors.initials: DR
authors.lastname: Leadley
authors.affiliation: National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA.
authors.forename: A V
authors.initials: AV
authors.lastname: Suslov
authors.affiliation: Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Green