title: Predicted pressure-induced spin and electronic transition in double perovskite R2CoMnO6 (R = rare-earth ion).
abstract: Specific first-principles calculations are performed to predict structural, magnetic and electronic properties of seven double perovskite R2CoMnO6 materials, with R being a rare-earth ion, under hydrostatic pressure. All these compounds are found to undergo a first-order transition from a high spin (HS) to low spin (LS) state at a critical pressure (whose value is dependent on the R ion). Such transition not only results in a significant volume collapse but also yields a dramatic change in electronic structure. More precisely, the HS-to-LS transition is accompanied by a transition from an insulator to a half-metallic state in the R2CoMnO6 compounds having the largest rare-earth ionic radius (i.e., Nd, Sm, Gd and Tb) while it induces a change from an insulator to a semiconductor having a narrow band gap for the smallest rare-earth ions (i.e., R = Dy, Ho and Er). Experiments are called for to confirm these predictions.
authors.affiliation: Laboratory of Dielectric Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China. Institute for Nanoscience and Engineering and Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors.forename: Hong Jian
authors.initials: HJ
authors.lastname: Zhao
authors.forename: Haiyang
authors.initials: H
authors.lastname: Zhou
authors.forename: Xiang Ming
authors.initials: XM
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Bellaiche