2001/07/09 by M. R. Sakr, Maryam Rahimi, S. V. Kravchenko +3
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.64.161308
published as Phys. Rev. B 64, 161308(R) (2001)
arxiv created 2001/07/09 · arxiv updated 2009/11/30
We show that in dilute metallic p-SiGe heterostructures, magnetic field can cause multiple quantum Hall-insulator-quantum Hall transitions. The insulating states are observed between quantum Hall states with filling factors ν=1 and 2 and, for the first time, between ν=2 and 3 and between ν=4 and 6. The latter are in contradiction with the original global phase diagram for the quantum Hall effect. We suggest that the application of a (perpendicular) magnetic field induces insulating behavior in metallic p-SiGe heterostructures in the same way as in Si MOSFETs. This insulator is then in competition with, and interrupted by, integer quantum Hall states leading to the multiple re-entrant transitions. The phase diagram which accounts for these transition is similar to that previously obtained in Si MOSFETs thus confirming its universal character.