Abstract
Results are presented of detailed numerical calculations for the spin excitations of a two-dimensional electron gas confined to a quantum well (QW) of finite width w, at magnetic fields corresponding to both fractional and integral Landau level (LL) fillings 1, 3, and 5. The Hamiltonian matrix of up to interacting electrons is diagonalized exactly in Haldane spherical geometry, neglecting excitations to higher orbital LL’s or to higher QW subbands. At sufficiently low Zeeman energy spin waves (SW’s) and skyrmions are found at that are composite fermion analogues of the reversed-spin-electron–hole excitations known to occur at Only for sufficiently large w are stable skyrmions found for and 5. Their stability depends upon the interaction pseudopotentials of their constituents. We propose a criterion on the pseudopotential needed for skyrmion stability, and construct phase diagrams (in the plane) for skyrmions of different size. The SW-SW and skyrmion-skyrmion interactions are also discussed, and the noninteracting SW condensates as well as the skyrmion fluids with Laughlin correlations (at intermediate skyrmion densities) are proposed.
- Received 26 September 2001
DOI:https://doi.org/10.1103/PhysRevB.66.045323
©2002 American Physical Society