Pan Lida, Song Boqun, Sun Jiatao, Zhang Lizhi, Hofer Werner, Du Shixuan, Gao Hong-jun
Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
J Phys Condens Matter. 2013 Dec 18;25(50):505502. doi: 10.1088/0953-8984/25/50/505502. Epub 2013 Nov 25.
We studied the mechanism of half-metallicity (HM) formation in transition-metal-doped conjugated carbon based structures by first-principles electronic structure simulations. It is found that the HM is a rather complex phenomenon, determined by the ligand field splitting of d-orbitals of the transition metal atoms, the exchange splitting and the number of valence electrons. Since most of the conjugated carbon based structures possess ligands with intermediate strength, the ordering of the d-orbital splitting is similar in all structures, and the HM properties evolve according to the number of valence electrons. Based on this insight we predict that Cr-, Fe- and Co-doped graphyne will show HM, while Mn- and Ni-doped graphyne will not. By tuning the number of valence electrons, we are thus able to control the emergence of HM and control the energy gaps evolving in the majority or minority spin channels.
我们通过第一性原理电子结构模拟研究了过渡金属掺杂共轭碳基结构中半金属性（HM）形成的机制。研究发现，半金属性是一种相当复杂的现象，它由过渡金属原子d轨道的配体场分裂、交换分裂和价电子数决定。由于大多数共轭碳基结构具有中等强度的配体，所有结构中d轨道分裂的顺序相似，半金属性性质根据价电子数而演变。基于这一见解，我们预测Cr、Fe和Co掺杂的石墨炔将表现出半金属性，而Mn和Ni掺杂的石墨炔则不会。通过调节价电子数，我们能够控制半金属性的出现，并控制在多数或少数自旋通道中演变的能隙。
