Zhao Hong Jian, Zhou Haiyang, Chen Xiang Ming, Bellaiche L
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.
J Phys Condens Matter. 2015 Jun 10;27(22):226001. doi: 10.1088/0953-8984/27/22/226001. Epub 2015 May 18.
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.
通过特定的第一性原理计算来预测七种双钙钛矿R2CoMnO6材料（其中R为稀土离子）在静水压力下的结构、磁性和电子性质。发现所有这些化合物在临界压力（其值取决于R离子）下会经历从高自旋（HS）到低自旋（LS）状态的一级转变。这种转变不仅导致显著的体积收缩，还会使电子结构发生巨大变化。更确切地说，在具有最大稀土离子半径的R2CoMnO6化合物（即Nd、Sm、Gd和Tb）中，从HS到LS的转变伴随着从绝缘体到半金属态的转变，而对于最小的稀土离子（即R = Dy、Ho和Er），它会引起从绝缘体到具有窄带隙半导体的变化。需要进行实验来证实这些预测。
