The crystal structure, chemical bonding, and magnetic properties of the intercalation compounds CrxZrTe2 (x = 0–0.3)

Abstract

New intercalation compounds Cr x ZrTe 2 were synthesized in the Cr concentration range of x = 0 -0.3. A thorough study of the crystal and electronic structure has been performed. It was found that there is competition in the distribution of the Cr atoms over the octa-and tetrahedral sites in the van der Waals gap, depending on the Cr content. The ordering of the Cr atoms was found at x = 0.25; at the same time, the lattice symmetry decreases from trigonal P-3m1 to monoclinic F2/m. This ordering stabilizes the octahedral coordination of the Cr atoms by Te atoms. The analysis of the experimental data on the electronic structure and DOS calculations showed that the Cr 3d states are spin-split.

Electronic and Crystal Structure of New CrxZrSe2 Intercalation Compounds

“…The question about the difference in the distribution of Cr atoms in the isostructural hosts TiCh 2 and ZrCh 2 (Ch = Se, Te) naturally arises. Concerning the octa-position, it has been found that the chemical bonding in M x TiCh 2 between the M intercalated atom and TiCh 2 host lattice is formed via hybridization of the M valence states and the states of the nearest-neighbor atoms, mainly Ti 3 d z 2 . ,,,, The hybrid states form a dispersionless band , below the Fermi level of the host compound. For a given host lattice, the binding energy of this band is directly proportional to the M atom ionization potential in the observed valence state.…”

“…Studying the Cr x ZrTe 2 compounds, we have found that the increase in Cr concentration up to x > 0.25 does not suppress the spin polarization of the Zr 4d/Cr 3d hybrid states. 17 We attribute this effect to the increased distance between the Cr atoms because the a 0 lattice parameter in ZrCh 2 is significantly higher than that in TiCh 2 . This reduces the overlap of the spin subbands and overcomes the suppression of the spin polarization at high intercalant concentrations.…”

“…Both Zr and Ti are in the same 4+ oxidation state, and the MCh 2 (M = Zr, Ti) lattices are isostructural ones. Studying the Cr x ZrTe 2 compounds, we have found that the increase in Cr concentration up to x > 0.25 does not suppress the spin polarization of the Zr 4d/Cr 3d hybrid states . We attribute this effect to the increased distance between the Cr atoms because the a 0 lattice parameter in ZrCh 2 is significantly higher than that in TiCh 2 .…”