Volume 78, Number 3, May 2007
Article Number 36002
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 27 April 2007
EPL, 78 (2007) 36002
DOI: 10.1209/0295-5075/78/36002

Possible role of $\chem{^{3}He}$ impurities in solid $\chem{^{4}He}$

Efstratios Manousakis

Department of Physics and MARTECH, Florida State University - Tallahassee, FL 32306-4350, USA and Department of Physics, University of Athens - Panepistimiopolis, Zografos, 157 84 Athens, Greece

received 2 January 2007; accepted in final form 27 March 2007; published May 2007
published online 27 April 2007

We use a quantum lattice gas model to describe essential aspects of the motion of 4He atoms and of 3He impurities in solid 4He. This study suggests that 3He impurities bind to defects and promote 4He atoms to interstitial sites which can turn the bosonic quantum disordered crystal into a metastable supersolid. It is suggested that defects and interstitial atoms are produced during the solid 4He nucleation process where the role of 3He impurities (in addition to the cooling rate) is known to be important even at very small (1 ppm) impurity concentration. It is also proposed that such defects can form a glass phase during the 4He solid growth by rapid cooling.

67.80.-s - Solid helium and related quantum crystals.
67.80.Mg - Defects, impurities and diffusion.
67.90.+z - Other topics in quantum fluids and solids; liquid and solid helium .

© Europhysics Letters Association 2007