Roton Density of States in Two-Dimensional Landau Level Excitations in Tilted Magnetic Fields

Roton structure in inter-Landau level excitations in a perpendicular magnetic field was first observed by Pinczuk et al. using resonant inelastic light scattering. Sine the electrons are confined to a quasi-two-dimensional layer, we expect the dispersion of these excitations to change when the magnetic field is no longer perpendicular to 2D electron layer. We find striking changes in the resonant Raman scattering of high-mobility GaAs heterostructures in tilted magnetic fields at integral filling factors.