Electronic structure of (GaAs)<sub>1-x</sub>Ge<sub>2</sub>: the relative importance of short-range and long-range order
J P Xanthakis; J P Xanthakis; Dept. of Electr. Eng., Nat. Tech. Univ., Athens, Greece
Журнал:
Journal of Physics: Condensed Matter
Дата:
1992-11-02
Аннотация:
The author calculates the electronic structure of (GaAs)<sub>1-x</sub>Ge<sub>2x</sub>, for which there are contradicting theories of the short-range structure. To investigate the latter he uses the cluster-Bethe-lattice method and the configuration-averaging technique of Gomez-Santos and Verges (1987) which can take into account diagonal and off-diagonal disorder as well as disorder in the short-range order parameters. His results are in good agreement with XPS spectra, and band gap, EXAFS and X-ray diffraction measurements. They point to models in which (i) no As-As or Ga-Ga bands exist, (ii) there is perfect coordination around each atom provided the atoms are not near grain boundaries and (iii) the fraction of antisites is very low for x<0.2 and then quickly goes to 0.5 at the critical value x<sub>c</sub> at which the zincblende-to-diamond transition occurs.
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