Observation of a new excitation in bcc 4He by inelastic neutron scattering.
We report neutron-scattering measurements of the phonons in bcc solid 4He. In general, only three acoustic phonon branches should exist in a monatomic cubic crystal. In addition to these phonon branches, we found a new "opticlike" mode along the [110] direction. One possible interpretation of this new mode is in terms of localized excitations unique to a quantum solid.
Markovich
T
T
Physics Department, Technion-IIT, Haifa, Israel 3200.
Polturak
E
E
Bossy
J
J
Farhi
E
E