Vacancion diffusion in body-centered cubic 3He crystals

Diffusion creep is measured in bcc 3He crystals for three values of the molar volume. The self-diffusion coefficients of 3He atoms in the interval 0.45–0.7 K are determined, along with the vacancion diffusion coefficients, which are found to be independent of the temperature. A method based on the model of wide-gap quasiparticles is proposed for determining the vacancion band gap Δυ directly by comparison of experimental self-diffusion and heat capacity data. The values obtained for Δυ are much greater than the temperature of the system, validating the underlying model of wide-gap quasiparticles.