Inelastic light-scattering measurements of low-lying collective excitations of electron double layers in the quantum Hall state at total filling nu(T) = 1 reveal a deep magnetoroton in the dispersion of charge-density excitations across the tunneling gap. The roton softens and sharpens markedly when the phase boundary for transitions to highly correlated compressible states is approached. The findings are interpreted with Hartree-Fock evaluations that link soft magnetorotons to enhanced excitonic Coulomb interactions and to quantum phase transitions in the ferromagnetic bilayers.

Observation of soft magnetorotons in bilayer quantum Hall ferromagnets

LUIN, Stefano;
2003

Abstract

Inelastic light-scattering measurements of low-lying collective excitations of electron double layers in the quantum Hall state at total filling nu(T) = 1 reveal a deep magnetoroton in the dispersion of charge-density excitations across the tunneling gap. The roton softens and sharpens markedly when the phase boundary for transitions to highly correlated compressible states is approached. The findings are interpreted with Hartree-Fock evaluations that link soft magnetorotons to enhanced excitonic Coulomb interactions and to quantum phase transitions in the ferromagnetic bilayers.
2003
Collective excitations, Quantum Hall Effects, Raman, electron bilayers, quantum well, semiconductor heterostructures, Hartree-Fock, Quantum Phase Transitions
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/2703
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