Positron affinity in semiconductors: Theoretical and experimental studies

摘要

Knowledge of the positron affinity A(+ ,) a basic hulk characteristic of materials, is important to the understanding of positron trapping at interfaces and at precipitates. Theoretical calculations of A(+) for 3C, 4H, and 6H polytypes of SiC, based on various approaches to electron-positron correlations within the local-density approximation and the generalized gradient approximation for positrons, are compared with experimental values obtained via work-function measurements. The disagreement between theoretical and experimental values of A(+) is discussed in terms of difficulties in the precise measurement of the positron work function and the possible inadequacy of contemporary approaches to electron-positron correlation in semiconductors. [S0163-1829(99)02303-6]. [References: 39]