Electronic structure of red mercuric iodide
D. E. Turner , B. N. Harmon
Physical Review B: Condensed Matter Vol. 40, No. 15, 10516-10522 (15 November 1989).
The self-consistent, relativistic electronic structure
of tetragonal mercuric iodide has been calculated. Significant
differences are found with the previously reported band structure
(e.g., a direct rather than indirect gap is obtained). The conduction
band is nearly isotropic for this layered crystal structure, while the
iodide p-like valence band is quite anisotropic. The charge transfer
between muffin-tin spheres centered on Hg and I sites is small,
indicating very little ionic bonding, while the band structure provides
clear evidence of strong covalent bonding.