Behavior of hydrogen ions, atoms, and molecules in alpha-boron studied using density functional calculations

Article

关键词: STABILITY;    HYDRIDES;   

DOI  :  10.1103/PhysRevB.83.024101

来源: SCIE

【 摘 要 】

We examine the behavior of hydrogen ions, atoms, and molecules in alpha-boron using density functional calculations. Hydrogen behaves as a negative-U center, with positive H ions preferring to sit off-center on interlayer bonds and negative H ions sitting preferably at in-plane sites between three B-12 icosahedra. Hydrogen atoms inside B-12 icosahedral cages are unstable, drifting off-center and leaving the cage with only a 0.09 eV barrier. While H-0 is extremely mobile (diffusion barrier 0.25 eV), H+ and H- have higher diffusion barriers of 0.9 eV. Once mobile, these defects will combine, forming H-2 in the interstitial void space, which will remain trapped in the lattice until high temperatures. Based on these results we discuss potential differences for hydrogen behavior in beta-boron and compare with experimental muon-implantation data.

【 授权许可】

Free