Theory of the copper vacancy in cuprous oxide.

Density-functional theory is used to examine aspects of the copper vacancy (V[SUBCu]) in cuprous oxide (Cu[SUB2]O). The normal vacancy configuration, obtained by simple removal of a Cu atom from the lattice, is found to be 0.1 eV higher in energy than a split vacancy configuration wherein a nearby Cu atom is displaced toward a normal vacancy site by half the bulk Cu-Cu separation. Jumps between the normal and split vacancy configurations are predicted to be rate limiting for V[SUBCu] diffusion with an energy barrier of 0.3 eV. Binding of V[SUBCu] to substitutional aluminum (Al[SUBCu]) and indium (In[SUBCu]) is examined. The neutral (Al[SUBCu] + 2 V[SUBCu]) complex is found to have a binding energy of 3.3 eV whereas the neutral (In[SUBCu] + 2 V[SUBCu]) complex is bound by 1.7 eV. The magnitudes of these binding energies suggest that Al[SUBCu] and In[SUBCu] should inhibit V[SUBCu] diffusion in Cu[SUB2]O. [ABSTRACT FROM AUTHOR]