论文标题
分子自旋中磁化的量子隧穿
Quantum tunneling of magnetization in molecular spin
论文作者
论文摘要
我们检查了由红野主方程的弱相互作用中分子自旋中磁化的量子隧穿。通过仅使用通用的哈密顿量并应用固定近似值的多级自旋系统的微观模型，我们为磁化过程的量子隧穿的量子方程式提供了一个关键运动方程，该运动适用于整个温度域。从这个方程式中，我们发现通常需要三个隧道速率来准确描述量子隧道过程。更重要的是，在不连贯和相干量子隧道之间存在过渡的中间温度域中的量子隧穿的行为也是第一次解开。还可以在重现一些流行的众所周知的结果的情况下，在低温和/或低磁场处限制案例。最后但并非最不重要的一点是，提出了对磁化的量子隧穿的新解释，我们在其中揭示了这种放松过程与驱动的阻尼谐波振荡器之间的相似性。
We examine the quantum tunneling of magnetization in molecular spin in weak interaction with a bath subject to Redfield master equation. By designing a microscopic model for a multilevel spin system using only a generic Hamiltonian and applying stationary approximation for excited doublets/singlets, we derive a key equation of motion for the quantum tunneling of magnetization process which is applicable in the whole temperature domain. From this equation, we find that in general three tunneling rates are needed to accurately describe the quantum tunneling process. More importantly, behavior of the quantum tunneling in the intermediate temperature domain where there exists a transition between incoherent and coherent quantum tunneling is also unraveled for the first time. Limiting cases at low and high temperature and/or low magnetic field are also worked out where some popular well-known results are reproduced. Last but not least, a new interpretation of the quantum tunneling of magnetization is proposed where we reveal the similarity between this relaxation process with a driven damped harmonic oscillator.
