First-Principles Study on Various Point Defects Formed by Hydrogen and Helium Atoms in Tungsten

Figure 1

The crystal structure of BCC W. The blue balls stand for the tungsten atoms, and the red ball stands for the H atom or He atom. A pure W supercell (a) and a W supercell contain a H atom or He atom in the substitutional site (b), tetrahedral site (c), and octahedral site (d).

(a)

(b)

(c)

(d)