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Density functional theory calculations of helium clustering in mono‐, di‐, and hexa‐vacancy in silicon
Author(s) -
Pizzagalli Laurent,
David MarieLaure,
Dérès Julien
Publication year - 2017
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201700263
Subject(s) - helium , vacancy defect , silicon , density functional theory , hexa , atomic physics , materials science , molecular physics , chemistry , crystallography , physics , computational chemistry , metallurgy
Abstract Combining classical molecular dynamics and first‐principles DFT calculations, we perfom an extensive investigation of low energy configurations for He n V m complexes in silicon. The optimal helium fillings are hence determined for V 1 , V 2 , and V 6 (figure on the right), and the structures formed by helium atoms arrangements in the vacancy defect are analyzed. For V 1 and V 2 , the He atoms structure is mainly controled by the host silicon matrix, whereas a high density helium packing is obtained for V 6 . For the latter, we estimate a helium density of about 170 He nm −3 in the center of the hexa‐vacancy at the optimal helium filling. Relaxed structures obtained from DFT calculations for configurations with the lowest formation energies: (a) He 14 V 1 , (b) He 20 V 2 , and (c) He 40 V 6 .