Comparative study of vacancies in the bcc and hcp phases of 4He using shadow wave functions

被引:1
作者
Chaudhuri, B [1 ]
Pederiva, F [1 ]
Chester, GV [1 ]
机构
[1] Cornell Univ, Atom & Solid State Phys Lab, Ithaca, NY 14853 USA
关键词
D O I
10.1023/A:1022569931554
中图分类号
O59 [应用物理学];
学科分类号
摘要
We use the shadow wave function formalism (SWF) to determine the energy of formation of single and double vacancies in He-4 crystals at T=0 K. Data is presented for both the bce and hcp phases. The activation energy for single vacancies in bcc He-4 was found to be 6.7+/-3.9 K, about 43% of that in the hcp He-4, 15.6+/-3.9 K. By determining the occupation of the Voronoi regions of the crystal sites, we determined the location of vacancies in the crystal and studied the relaxation of the neighboring atoms. We also present data on the correlations between vacancies, and between vacancies and He-3 impurities. Following the position of the vacancy through successive configurations we observed the motion of the vacancy as seen in our Monte Carlo simulations. On the shorter Monte Carlo time scales, greater vacancy motion was observed in the bcc phase than in the hcp phase.
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页码:751 / 756
页数:6
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