ISSN:
1432-0630
Keywords:
61.70
;
78.70
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract Two-Dimensional Angular Correlation of positron Annihilation Radiation (2D-ACAR) experiments have been performed on n-type GaAs. By combining these results with those from positron lifetime experiments, the momentum distribution of the arsenic vacancy in its neutral (V aAs 0 ) and negative (V As − ) charge states have been extracted. These distributions were all normalized to the respective positron lifetime that characterizes them. The first thing to be noticed is that the momentum distributions of the vacancies, as seen by the positron, are fairly isotropic and structureless. The distribution forV As 0 is more peaked than that ofV As − while the latter is more intense in the large momentum regions of the spectra. From this, it can be inferred that VA. has a smaller open volume thanV As 0 A closer look at the momentum distribution of the vacancies reveals that they are not entirely isotropic, but, in fact, have a bulk-like component. Finally, the experimental results for bulk GaAs andV As − compare well in a qualitative manner with the momentum distributions that result from an ab-initio molecular dynamics calculation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01571688
