Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
J Am Chem Soc. 2010 Mar 24;132(11):3682-4. doi: 10.1021/ja910483b.
Molecular spintronics has received extensive interest in recent years. Due to their favorable properties such as long spin coherence lengths and an amenability to fine-tuning via chemical substituents, organic materials play a prominent role in this field. Here we discuss how organic radicals may act as spin filters in the coherent tunneling regime and how they may be tuned to filter either majority- or minority-spin electrons by adding electron-donating or -withdrawing substituents. For a set of benzene-based model systems, we identify dips in the spin-resolved transmission, which may be caused by destructive interference, as a desirable feature when aiming for efficient spin filtering. Furthermore, the qualitative predictions made for our model systems are shown to be transferable to larger stable radicals.
近年来，分子自旋电子学受到了广泛关注。由于有机材料具有自旋相干长度长、易于通过化学取代基进行微调等优良性质，因此在该领域发挥着重要作用。本文讨论了有机自由基如何在相干隧穿区域充当自旋滤波器，以及如何通过添加供电子或吸电子取代基来调节其对多数自旋或少数自旋电子的过滤。对于一组基于苯的模型体系，我们发现自旋分辨透射中的谷可能是由相消干涉引起的，这是实现高效自旋过滤的理想特征。此外，我们还证明了对模型体系的定性预测可推广到更大的稳定自由基。
