MXenes结构Mo2C,Zn2N和Pb2C的第一性原理研究  

First principles study on the electronic properties of monolayer mxenes: Mo2C, Zn2N and Pb2C

作　　者：王悦 王立英[1] 陈红建 WANG Yue;WANG Liying;CHEN Hongjian(Faculty of Science,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学理学院

出　　处：《功能材料》2019年第11期11057-11064,共8页Journal of Functional Materials

基　　金：国家杰出青年科学基金资助项目(51701138);天津市自然科学基金资助项目(17JCQNJC02800,16JCYBJC17200)

摘　　要：基于密度泛函理论,研究了MXenes结构Mo2C,Zn2N和Pb2C系列材料的电子结构、磁结构以及双轴对称应力的影响。研究发现,Mo2C平衡晶格参数下为半金属(half-metal),并且具有高达8.0μB的超大磁矩和4.5 eV的半金属带隙;Zn2N在平衡晶格参数下表现为"准金属"(semimetal)特性,而Pb2C则为普通无磁性金属材料。在面内双轴对称应力作用下,Mo2C在很大畸变范围内均能很好保持良好的半金属性;Zn2N的准金属特性对于拉伸应力不敏感,而压缩应力下其semimetal能带结构较容易被破坏;压缩应力作用下,Pb2C可以实现由普通无磁性金属转变为semimetal。作为已开发出的为数不多的MXenes结构自旋电子学材料,该系列材料将是未来低维自旋电子学材料的良好候选材料。In this paper, the crystal structures, band structures, densities of states and the effect of biaxial symmetric strains on the electronic properties of monolayer MXenes: Mo2C, Zn2N and Pb2C were systematically investigated by using the first principles calculations. The calculated results show that Mo2C was a stable half-metal with a large half-metallic band gap of 4.5 eV at the equivalent lattice parameter. And the total magnetic moment of Mo2C was as large as 8.0 μB per formula unit. Meanwhile, Zn2N showed a "semimetal" character at the equilibrium lattice parameter, while Pb2C was an ordinary non-magnetic metal. Because the electronic properties and magnetic moment could usually be affected by the external strain for the two-dimensional materials, the strain effect of the electronic properties and magnetism on Mo2C, Zn2N and Pb2C were also discussed.It is found that the half-metallicity of Mo2C could be maintained in a wide biaxial symmetric strain range. For Zn2N, it was quite insensitive to the tensile stres. However, the semi-metallic property of Zn2N could be easily destroyed under the compressive biaxial symmetric strain. For Pb2C, it could become into a semimetal at the compressive biaxial symmetric strain. As one of the few MXenes spintronics materials that have been developed, this series of materials, especially Mo2C, would be a good candidate for low-dimensional spintronics materials in the future.

关 键 词：第一性原理计算 能带结构 能态密度 晶格畸变 MXenes 

分 类 号：O482[理学—固体物理]