We present analytical results concerning the magneto-roton instability in higher Landau levels evaluated in the single mode approximation. The roton gap appears at a finite wave vector, which is approximately independent of the LL index n, in agreement with numerical calculations in the composite-fermion picture. However, a large maximum in the static susceptibility indicates a charge density modulation with wave vectors q_0(n)∼ 1/√(2n+1), as expected from Hartree-Fock predictions. We thus

more »

... n a unified description of the leading charge instabilities in all LLs.