Properties of Vacancy Formation in He-4 hcp Crystals at Zero Temperature and Fixed Pressure
Other Condensed Matter
2011-12-30 v1
Abstract
Equation of state of He-4 hcp crystals with vacancies is determined at zero temperature using the diffusion Monte Carlo technique, an exact ground state zero-temperature method. This allows us to extract the formation enthalpy and isobaric formation energy of a single vacancy in otherwise perfect helium solid. Results were obtained for pressures up to 160 bar. The isobaric formation energy is found to reach a minimum near 57 bar where it is equal to K. At the same pressure, the vacancy formation volume exhibits a maximum and reaches the volume of the unit cell. This pressure coincides with the pressure interval over which a peak in the supersolid fraction of He-4 was observed in a recent experiment.
Cite
@article{arxiv.1007.0161,
title = {Properties of Vacancy Formation in He-4 hcp Crystals at Zero Temperature and Fixed Pressure},
author = {Y. Lutsyshyn and C. Cazorla and G. E. Astrakharchik and J. Boronat},
journal= {arXiv preprint arXiv:1007.0161},
year = {2011}
}