Collective excitations of quantum Hall states under tilted magnetic field

Abstract

We study the neutral excitations of fractional quantum Hall states in electronic systems of finite width where an external anisotropy is introduced by tilting the magnetic field. As in the isotropic case, the neutral collective excitation can be worked out through the conserving method of composite fermions in the Hamiltonian theory because the interaction potential has a natural cutoff due to the quantum well width. We show how such a computation can be carried out perturbatively for an anisotropic interaction. We find that unlike the charge gap, the neutral collective gap is much more sensitive to the tilt and can thus, for certain fractional quantum Hall states, be easily destroyed by the parallel component of the magnetic field. We also discuss the convergence of the collective spectrum to the activation gap in the large-momentum limit.

References in corpus (5)

• Theory of Nematic Fractional Quantum Hall State
• Anisotropic Pseudopotential Characterization of Quantum Hall Systems under Tilted Magnetic Field
• $\nu =1/2$ Fractional Quantum Hall Effect in Tilted Magnetic Fields
• Shape of the magnetoroton at $\nu =1/3$ and $\nu =7/3$ in real samples
• Quantum Hall stripes in high-density GaAs/AlGaAs quantum wells