Inelastic neutron scattering studies have been performed on single crystals of TmSe. An excitation at $\hslash \omega \sim 10$ meV is observed whose momentum, temperature, and sample dependences provide evidence that this spectral features is due to an excitation across a hybridization gap in TmSe.

• Received 27 October 1981

DOI:https://doi.org/10.1103/PhysRevB.25.1457