Relativistic and core-relaxation effects on the energy bands of gallium arsenide and germanium.

摘要: Relativistic self-consistent band-structure calculations using either norm-conserving pseudopotentials or the linear-muffin-tin-orbital method (LMTO) demonstrate that relativistic effects on some conduction bands of gallium arsenide, if qualitatively not unexpected, are however, surprisingly large (the direct gap is reduced by one-half), despite relatively light atoms. This discussed in terms a simple bonding-antibonding picture: may be depressed amplified, with respect to free atoms, formation and bonds. The 3d core states known shallow, i.e., far enough from 4s 4p energies allow them treated as completely frozen-core states. Therefore, new LMTO calculation we treat same footing other valence-band most evident Ga core-relaxation further, sizable shrinkage gaps, clear improved agreement valence photoemission experiments. We stress influence GaAs, also show, for first time, intrinsic failure local-density approximation gaps concerned much larger third-row semiconductors than for, e.g., better-known case Si. emphasized our neighboring elemental semiconductor, germanium, where almost no found, metallization has occurred one row too early. calculated necessary reference development density-functional theory energy gap.