Strain-Induced Isostructural and Magnetic Phase Transitions in Monolayer MoN2
Strain-Induced Isostructural and Magnetic Phase Transitions in Monolayer MoN2
复制标题
单层 MoN2 中应变诱导的同构和磁相变
DOI：
10.1021/acs.nanolett.6b01841
复制
发表时间：
2016
期刊：
影响因子：
10.8
通讯作者：
Yang Shengyuan A.
中科院分区：
文献类型：
--
作者：
Wang Yao;Wang Shan-Shan;Lu Yunhao;Jiang Jianzhong;Yang Shengyuan A.
通常只在化学过程中发生的键合状态的改变会极大地改变材料的性能。在这里，我们表明可以通过物理手段，即通过适度的双轴应变，在新发现的mon2二维（2D）材料中实现可调的双原子键断裂和形成。根据第一性原理计算，我们预测在应变作用下，随着晶格参数的增加，存在一个N-N距离突然下降的同结构相变，对应于从N-N非键态到N-N单键态的转变。值得注意的是，成键变化还引起了磁相变，其间磁矩从N（2p）亚晶格转移到Mo（4d）亚晶格；同时，磁耦合的类型由铁磁性变为反铁磁性。我们为理解这些显著的效应提供了一幅物理图景。这一发现不仅对探索低维系统中不寻常的相变具有重大的科学意义，而且还揭示了二维mon2材料在纳米机械、电子和自旋电子应用方面的巨大潜力。
The change of bonding status, typically occurring only in chemical processes, could dramatically alter the material properties. Here, we show that a tunable breaking and forming of a diatomic bond can be achieved through physical means, i.e., by a moderate biaxial strain, in the newly discovered MoN2two-dimensional (2D) material. On the basis of first-principles calculations, we predict that as the lattice parameter is increased under strain, there exists an isostructural phase transition at which the N–N distance has a sudden drop, corresponding to the transition from a N–N nonbonding state to a N–N single bond state. Remarkably, the bonding change also induces a magnetic phase transition, during which the magnetic moments transfer from the N(2p) sublattice to the Mo(4d) sublattice; meanwhile, the type of magnetic coupling is changed from ferromagnetic to antiferromagnetic. We provide a physical picture for understanding these striking effects. The discovery is not only of great scientific interest in exploring unusual phase transitions in low-dimensional systems, but it also reveals the great potential of the 2D MoN2material in the nanoscale mechanical, electronic, and spintronic applications.