Using the first-principles calculations, we investigate the structural, electronic, and magnetic properties of 3d transition metal (TM) (TM = Co, Cu, Mn, Fe, and Ni) atoms substitutional doping of SnSe monolayer. Magnetism is observed for Co, Mn, Fe, and Ni doping. In particular, Mn- and Fe-substituted systems exhibit large magnetic moment of 5.0 and 4.0μB at a very low impurity concentration. Then, we study the magnetic coupling in these two substituted systems. The magnetic coupling between two Mn atoms prefers to antiferromagnetic (AFM) owing to the super exchange between d states of two Mn atoms. Interestingly, both AFM and ferromagnetic (FM) coupling are observed in two-Fe-doped systems. Due to the strong spin–orbit coupling between Fe-3d and Se-4p, a long-range FM interaction is found in the Fe-substituted system. Our results demonstrate potential applications of TM-substituted SnSe for spintronics and magnetic storage devices.

使用第一性原理计算，我们研究了SnSe单层的3d过渡金属（TM）（TM = Co，Cu，Mn，Fe和Ni）原子取代掺杂的结构，电子和磁性。观察到Co，Mn，Fe和Ni掺杂的磁性。尤其是，Mn和Fe取代的系统在非常低的杂质浓度下表现出5.0和4.0μB的大磁矩。然后，我们研究了这两个替代系统中的磁耦合。由于d之间的超级交换，两个Mn原子之间的磁耦合更倾向于反铁磁（AFM）两个Mn原子的状态。有趣的是，在两铁掺杂的系统中观察到了AFM和铁磁（FM）耦合。由于Fe-3d和Se-4p之间的强自旋轨道耦合，在Fe取代的系统中发现了长距离FM相互作用。我们的结果证明了TM取代的SnSe在自旋电子学和磁性存储设备中的潜在应用。