Skyrmions and the crossover from the integer to fractional quantum Hall effect at small Zeeman energies
Abstract
We study the twodimensional electron gas in a high magnetic field at filling factor ν=1 for an arbitrary ratio of the Zeeman energy gμ_{B}B to the typical interaction energy. We find that the system always has a gap, even when the oneparticle gap vanishes, i.e., when g=0. When g is sufficiently large, the quasiparticles are perturbatively related to those in the noninteracting limit; we compute their energies to second order in the Coulomb interaction. For g smaller than a critical value g_{c} the quasiparticles change character; in the limit of g>0, they are skyrmionsspatially unbounded objects with infinite spin. In GaAs heterojunctions, the gap is unambiguously predominantly due to correlation effects; indeed, we tentatively conclude that g is always smaller than g_{c}, so the relevant quasiparticles are the skyrmions. The generalization to other oddinteger filling factors, and to ν=1/3 and 1/5, is discussed.
 Publication:

Physical Review B
 Pub Date:
 June 1993
 DOI:
 10.1103/PhysRevB.47.16419
 Bibcode:
 1993PhRvB..4716419S
 Keywords:

 73.40.Hm;
 71.27.+a;
 Strongly correlated electron systems;
 heavy fermions