Lattice dynamics of LiBC

We have investigated the lattice dynamics of LiBC at various annealing temperatures. Experimental Raman and inelastic neutron-scattering results are confronted with density-functional calculations. The excellent agreementbetween experiment and theory indicates that we have attained a high level of understanding for LiBC, which by its structure is closely related to superconducting MgB 2 . We will show that annealing of the sample is insufficient to cause Li deficiency and thus produce the expected superconductivity.