X-ray Topographs of Solid Helium

Liquid 3He and 4He differ in stability from all other materials. They do not become a solid phase at T=0K, because of their giant zero-point vibration. This means that 3He and 4He have almost the same kinetic energy but have nearly no potential minimum that is required to stabilize a solid phase. Therefore, liquid 3He and 4He can transform into solid phases called "quantum crystal", with the aid of pressure of about 30 atm. Laue spots 110 for the case of a 3He solid phase, taken at 0.3K using white X-rays, are shown in the figures.

The subboundaries of solid 3He parallel to the gradients of temperature and pressure changes with annealing time, as indicated by arrows. This change might be understood from the quantum tunneling, because of lack of the thermal activation process.
[PF Home Page]