EXACT EXCHANGE POTENTIAL BAND-STRUCTURE CALCULATIONS BY THE LINEAR-MUFFIN-TIN-ORBITAL ATOMIC-SPHERE APPROXIMATION METHOD FOR SI, GE, C, AND MNO

We present electronic band-structure calculations which use the exact Kohn-Sham density-functional exchange potential instead of the exchange potential exploited in the local density approximation (LDA). We treat Si, Ge, diamond, and antiferromagnetic MnO. The calculated band gaps are much larger than those obtained by the LDA, e.g., 1.93 eV for Si while 0.45 eV in the LDA. Our calculation suggests also that MnO is a Mott-Hubbard insulator with a large band gap. The calculated exact exchange potentials show significant structures reflecting the atomic shells. © 1995 The American Physical Society.