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Quasiparticle band structure of silicon carbide polytypes
No full textThe ab initio pseudopotential method within the local-density approximation and the quasiparticle
approach have been used to investigate the electronic excitation properties of hexagonal (6H, 4H,
2H) and zinc-blende (3C) silicon carbide. The quasiparticle shifts added to the density-functional
eigenvalues are calculated using a model dielectric function and an approximate treatment of the
electron self-energy concerning local-field effects and dynamical screening. The inverse dielectric
function and the auxiliary function are generalized to hexagonal crystals. Good agreement with
the experimental results is obtained for the minimum indirect energy gaps. The k space location
of the corresponding conduction-band minima is clarified. Other excitation energies are predicted.
The in6uence of the quasiparticle effects on band discontinuities and the electron effective masses is
studied
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