The electronic structure of the metastable layer compound 1T-CrSe2

The electronic structure of the metastable compound 1T-CrSe2 (a = 3.399 Å, c = 5.911 Å, space group P_3m1) was calculated with and without spin polarization using the LSW method. The energy is 0.29 eV/mol CrSe2 lower for the spin-polarized calculation. The total magnetic moment of +2.44 μB on Cr consists of 3.28 μB in spin-up and 0.84 μB in spin-down states; the total number of 3d electrons on Cr is 4.12, much greater than expected for Cr(IV) 3d2. The Cr 3d-based bands overlap the selenium 4p-based valence band which implies strong covalency of the Cr–Se bonding. At the Fermi level there are electrons and holes with Cr 3d character, and holes with Se 4p character. 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 difference between the magnetic and non-magnetic states, indicating that VSe2 is a non-magnetic metal