Communication: The reason why +c ZnO surface is less stable than -c ZnO surface: first-principles calculation.
It has been experimentally shown that an O(-c)-polar ZnO surface is more stable than a Zn(+c)-polar surface in H(2) ambient. We applied first-principles calculations to investigating the polarity dependence on the stability at the electronic level. The calculations revealed that the -c surface terminated with H atom was stable maintaining a wurtzite structure, whereas the +c surface was unstable due to the change of coordination numbers of Zn at the topmost surface from four (wurtzite) to six (rock salt). This causes the generation of O(2) molecules, resulting in instability at the +c surface.
National Institute for Materials Science, Tsukuba, Japan.
Seitaro
S
Ito
Tomomi
T
Shimazaki
Momoji
M
Kubo
Hideomi
H
Koinuma
Masatomo
M
Sumiya