THE ELECTRONIC-STRUCTURE OF THE METASTABLE LAYER COMPOUND 1T-CRSE2

The electronic structure of the metastable compound 1T-CrSe2 (a = 3.39 9 Angstrom, c = 5.911 Angstrom, space group P (3) over bar m1) was cal culated with and without spin polarization using the LSW method. The e nergy is 0.29 eV/mol CrSe2 lower for the spin-polarized Calculation. T he total magnetic moment of +2.44 mu(B) on Cr consists of 3.28 mu(B) i n spin-up and 0.84 mu(B) in spin-down states; the total number of 3d e lectrons on Cr is 4.12,:much greater than expected for Cr(TV) 3d(2). T he Cr 3d-based bands overlap the selenium 4p-based valence band which implies strong covalency of the CrSe bonding. At the Fermi level there are electrons and holes with Cr 3d character, and holes with Se 4p ch aracter. The results clearly indicate the reduction of the cations and the presence of holes in the Se 4p valence band. CrSe2 is a magnetic metal. Similar calculations for VSe2 showed a very small energy differ ence between the magnetic and non-magnetic states, indicating that VSe 2 is a non-magnetic metal.