We present ab initio electronic structure calculations for the Si-terminated SiC(0001)root 3 X root 3 surface. While local-density approximation (LDA) calculations predict a metallic ground state with a half-filed narrow band, Coulomb effects, included by the spin-polarized LDA+U method, result in a magnetic (Mott-Hubbard) insulator with a gap of 1.5 eV, comparable with the experimental value of 2.0 eV. The calculated value of the intersite exchange parameter, J=30 K, leads to the prediction of a paramagnetic Mott state, except at very low temperatures. The observed Si 2p surface core-level doublet can naturally be explained as an on-site exchange splitting.
SiC(0001): A surface Mott-Hubbard insulator / Anisimov, V. I.; Bedin, A. E.; Korotin, M. A.; Santoro, Giuseppe E.; Scandolo, S.; Tosatti, E.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 61:3(2000), pp. 1752-1755. [10.1103/PhysRevB.61.1752]
SiC(0001): A surface Mott-Hubbard insulator
Santoro, Giuseppe E.;Tosatti, E.
2000-01-01
Abstract
We present ab initio electronic structure calculations for the Si-terminated SiC(0001)root 3 X root 3 surface. While local-density approximation (LDA) calculations predict a metallic ground state with a half-filed narrow band, Coulomb effects, included by the spin-polarized LDA+U method, result in a magnetic (Mott-Hubbard) insulator with a gap of 1.5 eV, comparable with the experimental value of 2.0 eV. The calculated value of the intersite exchange parameter, J=30 K, leads to the prediction of a paramagnetic Mott state, except at very low temperatures. The observed Si 2p surface core-level doublet can naturally be explained as an on-site exchange splitting.| File | Dimensione | Formato | |
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