Mn和Co线性单原子链填充Cu纳米管的稳定性和磁性
Stability and magnetic properties of Mn and Co linear monoatomic chains encapsulated into copper nanotube

基于密度泛函理论框架下的第一性原理计算，系统地研究了过渡金属(TM) Mn和Co线性单原子链填充Cu纳米管所形成复合结构的稳定性和磁性。相对于孤立单原子链，复合结构的结合能大大增加，表明Cu纳米管的包裹使得Mn和Co单原子链的稳定性显著增强。随着管内TM原子间距的增加，Mn@CuNT复合结构表现出由反铁磁向铁磁的磁相变，而Co@CuNT复合结构则表现出由铁磁向反铁磁的磁相变。相对于自由单原子链，复合结构的磁晶各向异性能显著增强，且Cu纳米管的包裹使得Mn原子链的易磁化方向发生了改变。
By using first-principles calculations based on density-functional theory, we have systematically investigated the stability and magnetic properties of transition metal (TM) Mn and Co linear monoatomic chains encapsulated into copper nanotube. The results indicate that the binding energies of the TM@CuNT hybrid structures are remarkably higher than those of freestanding TM chains, suggesting that the TM chains are signi？cantly stabilized by the copper nanotube coating. The magnetic phase transitions from antiferromagnetic state to ferromagnetic state in Mn@CuNT hybrid structure and from ferromagnetic state to antiferromagnetic state in Co@CuNT hybrid structure take place when the TM-TM atom distances increase. The magnetic phase transition can be understood by RKKY model. The magnetocrystalline anisotropy energies (MAE) of TM@CuMT hybrid structures are all remarkably enhanced compared to those of free TM chains and a trend that longer TM-TM distance results in a larger MAE. Furthermore, the easy magnetization axis of Mn@CuNT hybrid structure switches from that perpendicular to the axis in the free Mn linear chain to that along the axis, which makes them possible for practical application.