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HL: Halbleiterphysik

HL 9: Poster I

HL 9.98: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Collective Excitations and Composite Fermions — •G. Meissner and U. Schmitt — Theoretische Physik, Universitaet des Saarlandes, Postfach 15 11 50, D-66041 Saarbruecken

Strong correlations are of significance in incompressible quantun liquid phases of interacting 2D electrons in high perpendicular magnetic fields exhibiting the fractional quantum Hall effect at certain fractional filling factors of the lowest Landau level. Therefore, dispersion relations of resulting collective excitations as magneto-rotons are reexamined and shown to be obtained in a non-perturbative many-body approach using intensively sum-rule techniques. Employing a Chern-Simons gauge theory in the Zeeman low-energy limit, finite wave-vector spin-flip excitations of integer quantum Hall states of Composite Fermions with corresponding integer filling factors are then investigate by summing up diagrams for their Coulomb interaction in shielded potential approximation. Compelling similarities found in the dispersion of these intra-Landau level and inter-Landau level excitations are finally discussed in view of a comparison with inelastic light-scattering experiments in such quantum Hall systems.