Details

Autor(en) / Beteiligte

• Biswas, S

Titel

Metal–insulator transition in the high pressure cubic CaF2-type structure of CrO2

Ist Teil von

• Bulletin of materials science, 2018-04, Vol.41 (2), p.33

Ort / Verlag

Bangalore, India: Indian Academy of Sciences

Erscheinungsjahr

2018

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The total energy, magnetic moment, density of states and energy band structures of CrO 2 in the high pressure cubic CaF 2 (Fm-3m)-type structure are investigated for the first time by using first principles electronic structure calculations based on density functional theory in the local spin density approximation (LSDA) as well as using LSDA + U method. It is revealed from the present study that CrO 2 is a ferromagnetic nearly half-metal in the LDA calculation due to almost occupied Cr-3de g orbitals in the spin majority species and a tiny electron contribution at the Fermi level ( E F ) for spin minority species. This compound encounters metal–insulator transition (MIT) upon the application of Hubbard-type Coulomb repulsion U = 1 eV . Ferromagnetism is preserved in this transition. Application of U increases the electron correlation, which polarizes e g orbitals far below E F for spin majority channel while in the spin minority channel e g orbitals are polarized well above E F , resulting in opening of a band gap ( E g ∼ 1.05 eV ) in the vicinity of E F . Coulomb repulsion increases hybridization between occupied Cr-3de g and O-2p orbitals, which induces ferromagnetism both in half-metallic and insulating phases of cubic CrO 2 .