We consider the influence of an external periodic potential on the fractional quantum Hall effect. For many electrons on a torus, we find that at finite system size L the splitting of incompressible ground-state degeneracies by a weak external potential is proportional to exp(-L/ξ). We present numerical results consistent with a scenario in which ξ diverges at a continuous phase transition from fractional to integer quantum Hall states which occurs at a critical periodic potential strength.
Physical Review B
- Pub Date:
- September 1997
- Metal-insulator transitions and other electronic transitions;
- Condensed Matter - Mesoscopic Systems and Quantum Hall Effect
- 4 pages, REVTeX, 3 epsf-embedded color postscript figures, submitted to PRB (Rapid Comm.), added reference in revised version