Abstract
Magnetorotons in the dispersions of collective gap excitation modes of fractional quantum Hall liquids are measured in resonant inelastic light scattering experiments. Two deep magnetoroton minima are observed at , while a single deep minimum is resolved at . The observations are the first evidence of multiple roton minima in gap excitations of the quantum liquids. The results support Chern-Simons and composite fermion calculations that predict multiple roton minima for states with .
- Received 5 October 2000
DOI:https://doi.org/10.1103/PhysRevLett.86.2637
©2001 American Physical Society