Reemergence of the collective mode in 3He and electron layers

Helga M. Böhm (1) , Robert Holler (1) , Eckhard Krotscheck (1) , Martin Panholzer (1) , Henri Godfrin (2) , Mathias Meschke , Hans-Jochen Lauter (3)

1 Institute for Theoretical Physics [Linz]
2 NEEL - UBT - Ultra-basses températures
3 ILL - Institut Laue-Langevin

Neutron scattering experiments on a3Helayer ongraphite show an unexpected behavior of the collective mode. After having been broadened by Landau damping at intermediate wave vectors, the phonon-roton mode resharpens at large wave vectors and even emerges from the particle-hole continuum at low energies. The measured spectra cannot be explained by a random phase approximation with any static interaction. We show here that the data are well described if dynamic two-pair fluctuations are accounted for. We predict similar effects for electron layers.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

Helga M. Böhm, Robert Holler, Eckhard Krotscheck, Martin Panholzer, Henri Godfrin, et al.. Reemergence of the collective mode in 3He and electron layers. International Journal of Modern Physics B, 2010, 24 (25-26), pp.4889. ⟨10.1142/S0217979210057079⟩. ⟨hal-00921240⟩