Microscopic approach to the bcc phase of solid ⁴He

Abstract

The coexistence between the hcp and bcc phases of solid ⁴He at fixed pressure, and at three different temperatures, is studied by means of the path integral Monte Carlo method. Microscopic results for the main energetic and structure properties of the two phases are reported. The differences between hcp and bcc ⁴He are shown to be small with the obvious exception of the static structure factor. When crossing the phase transition line, the most significant changes are observed in the kinetic energy per particle and in the Lindemann ratio, both pointing to a less correlated quantum solid in the bcc side. No off-diagonal long-range order is observed in the hcp and bcc perfect lattices.

Keywords:

• solid ⁴He
• bcc phase
• quantum Monte Carlo

Acknowledgments

The authors acknowledge partial financial support from the DGI (Spain) Grant No. FIS2008-04403 and Generalitat de Catalunya Grant No. 2009SGR-1003.