Calculation of formation energies of intrinsic point defects in In$_{3}$La

We use \textit{perturbed angular correlation of gamma rays}, or PAC, to measure jump frequencies of $^{111}$In/Cd probe atoms in In$_{3}$La and related phases (see Phys. Rev. Lett. 92, 225019 (2004)). To interpret the jump frequencies, first principles calculations were used to determine energies of intrinsic vacancy and antisite atom defects. In$_{3}$La has the L1$_{2}$ structure in which four possible combinations of vacancies and antisite atoms can be thermally activated that maintain the homogeneity of the phase. Formation energies of the defect combinations were calculated using the electronic structure code WIEN2k that is based on density functional theory. Partial formation energies were found to be least for La$_{In}$, at 0.71 eV, and V$_{In}$, at 1.47 eV, with much greater energies for In$_{La}$ and V$_{La}$ defects. Formation energies per defect of the four defect combinations all had similar values, but the antisite pair, La$_{In}$ + In$_{La}$, had the lowest value. \textit{This work was supported by the NSF under grant DMR 05-04843 (Metals Program).}