First-principles study of the new compounds CrGa2Sb2 and CrGaSb synthesized under high pressure
A.M. Prokhorov General Physics Institute, Russian Academy of Sciences - 119991 Vavilov str. 38, Moscow, Russia
2 L.F. Vereshchagin Institute for High Pressure Physics, Russian Academy of Sciences - 142190 Troitsk, Moscow region, Russia
3 P.N. Lebedev Physical Institute, Russian Academy of Sciences - 119991 Leninskii prosp. 53, Moscow, Russia
Accepted: 3 September 2011
We present the density-functional calculations of the compounds CrGa2Sb2 and CrGaSb synthesized recently under high pressure. Calculation reproduces well all details of the crystal structure of these compounds, their spin ordering, and a larger metallicity of CrGaSb comparing to CrGa2Sb2. Particular attention is given to the room temperature ferromagnetic compound CrGa2Sb2, where the huge resistivity hinting at the possible semiconducting properties was measured. To understand the mechanism of its anisotropic conductivity, we analyze the band structure, calculated kinetic and optical characteristics of this compound. It is found that the density of states of CrGa2Sb2 has a pseudogap near the Fermi level, where the Cr atoms do not dominate, but contribute even less than the atoms of Ga and Sb. This explains a very high calculated resistivity of CrGa2Sb2, which can be characterized as a ferromagnetic compound with a low metallic conductivity. This type of conductivity remains unchanged, when a possible Cr-deficiency of CrGa2Sb2 is taken into account or the MBJ-LDA exchange-correlation potential is used instead of the GGA-LDA one in calculation. The potential of this compound for the development of spintronic materials is discussed.
PACS: 71.20.-b – Electron density of states and band structure of crystalline solids / 75.30.-m – Intrinsic properties of magnetically ordered materials / 75.50.-y – Studies of specific magnetic materials
© EPLA, 2011