Crossing and anticrossing of spin-split Landau levels in an AlxGa1-xAs/GaAs parabolic quantum well ferromagnet
Abstract
An electric field modulation technique is used to measure directly the second derivative with respect to gate voltage of Shubnikov-de Haas oscillations for an AlGaAs/GaAs parabolic quantum well with two spatially coincident populated subbands. This technique resolves the spin-split regions in the topological phase diagram and allows observation of the two-subband Landau fan diagram in fine detail. We observe, and model with an effective g factor, the curved Landau levels of the first and second subbands in a tilted magnetic field. We obtain evidence for intersubband mixing, but the details are not in accord with present theory. For certain applied electric and magnetic fields, quantum Hall ferromagnetic ground states are also observed.
- Publication:
-
Physical Review B
- Pub Date:
- August 2007
- DOI:
- 10.1103/PhysRevB.76.085331
- Bibcode:
- 2007PhRvB..76h5331Y
- Keywords:
-
- 73.21.Fg;
- 73.63.Hs;
- 73.43.-f;
- 71.70.Di;
- Quantum wells;
- Quantum wells;
- Quantum Hall effects;
- Landau levels