Abstract
The single atom kinetic energy of high purity solid hcp has been measured by neutron Compton scattering, at temperatures between 0.07 and 0.4 K and a pressure of 40 bar. Within statistical error of no change in was observed. The values of at were the same in a single crystal and a polycrystalline sample and were also unaffected (within statistical error) by the addition of 10 ppm of . The lattice constant was also found to be independent of temperature to within 1 part in 2000. These results suggest that the supersolid transition in has a different microscopic origin to the superfluid transition in the liquid.
- Received 22 September 2006
DOI:https://doi.org/10.1103/PhysRevLett.98.085301
©2007 American Physical Society