线性磁性分子离子中由激光诱导的超快自旋转移

Laser-induced ultrafast spin transfer in linear magnetic molecular ions

通过由激光诱导的A进程,很多分子磁性体系中涉及的退磁、自旋翻转或自旋转移过程在理论上得以实现.本文针对具有线性构型的磁性分子离子,应用量子化学从头计算与自编程序相结合的方法,实现了具有线性构型的双磁性中心分子体系[Fe-O-Co]^+中基于A进程的超快自旋转移,且电子占据的转移率达到90%以上.本文的理论研究结果表明,采用改变磁场方向的方法来增强体系的磁晶各向异性,可以避免为提高自旋转移能力而额外增加桥接原子在实际应用中的复杂性,同时也可明显提高电子占据的转移率.

The demagnetization, spin switching, and spin transfer in magnetic molecular systems can be theoretically achieved via the laser-induced Λ process. In the present work, both quantum chemistry ab initio calculations and our self-written programs are adopted to investigate the spin-transfer behavior of the magnetic molecular ions with linear configuration. It is shown for the first time that the Λ process based ultrafast spin transfer can be achieved in a linear two-magnetic-center molecular ion [Fe-O-Co]＋, and the fidelity of the population transfer exceeds 90%. The present theoretical prediction shows that the magnetocrystalline anisotropy of a molecular system can be enhanced by properly adjusting the direction of the applied magnetic field, which is shown to be a better way to improve the spin-transfer ability of the molecular system than by increasing additional bridging atoms since it could avoid the complexity of the latter situation in practical applications. At the same time, the present spin-transfer scenario indicates that the fidelity of the population transfer could also be evidently increased.