Challenges in predicting positron annihilation lifetimes in lead halide perovskites: correlation functionals and polymorphism
This study demonstrates that the choice of electron-positron correlation functional, particularly the use of the non-local weighted density approximation (WDA), is critical for accurately predicting positron annihilation lifetimes in lead halide perovskites, revealing that previous discrepancies in theoretical predictions and experimental interpretations of cation vacancies stem from the sensitivity of these materials to the specific approximation used.