论文标题
单磁分子中磁态的电场调谐
Electric field tuning of magnetic states in single magnetic molecules
论文作者
论文摘要
单磁分子可能是最小的功能磁铁。电场可控的磁分子的旋转状态对于应用而言至关重要，而其实现仍然具有挑战性。迄今为止，基于自旋轨道耦合或自旋偶极偶联的观察到的自旋电相互作用可用于调整细旋转结构，但太弱，无法翻转旋转状态。在这项工作中，我们提出了一种新的机制，以实现增强的自旋电耦合，并通过调整局部旋转之间的自旋大量缩短来翻转自旋状态。使用第一原理计算和海森伯格哈密顿量，我们在磁分子家族（过渡金属卟啉）中证明了这种效果。我们表明它们的D-π和π-π自旋superexchange耦合由D和π电子状态的相对能量确定，这些态对施加的电场敏感。因此，应用电场可以调整多种磁接地态，包括铁磁，铁磁和抗铁磁构型。这种自旋电耦合可以为设计和控制分子旋转的新方法提供新的方法。
Single magnetic molecules may be the smallest functional magnets. An electric-field controllable spin state of magnetic molecules is of fundamental importance for applications while its realization remains challenging. To date the observed spin-electric interaction based on spin-orbit coupling or spin dipole coupling is useful to tune fine spin structures but too weak to flip the spin state. In this work, we propose a new mechanism to realize enhanced spin-electric coupling and flip the spin states by tuning the spin superexchange between local spins. Using first-principles calculations and Heisenberg Hamiltonian, we demonstrate this effect in a family of magnetic molecules, transition metallic Porphyrins. We show that their d-π and π-π spin superexchange couplings are determined by the relative energies of d and π electronic states, which are sensitive to the applied electric field. Therefore, applying electric field can tune a wide range of magnetic ground states, including ferromagnetic, ferrimagnetic, and antiferromagnetic configurations. This spin-electric coupling may provide a new approach for designing and controlling molecular spintronics.
