Tuning of spin-orbit coupling in metal-free conjugated polymers by structural conformation
Tuning of spin-orbit coupling in metal-free conjugated polymers by structural conformation
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DOI：
10.1103/physrevmaterials.4.085603
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发表时间：
2020-08-28
影响因子：
3.4
通讯作者：
Sun, Dali
中科院分区：
文献类型：
--
作者：
Vetter, Eric;VonWald, Ian;Sun, Dali
自旋-轨道耦合（SOC）的控制是自旋-轨道电子应用的关键成就，因为SOC决定了自旋扩散长度和自旋-电荷转换效率。虽然在大多数有机半导体中，SOC由于主要由轻元素组成而固有地非常弱，但共轭聚合物体系中的SOC也与聚合物的结构构象密切相关，因此可以被操纵。在这里，我们报告的修改SOC共轭聚合物通过改变扭转角共轭单元之间。自旋泵浦实验进行了三个聚（3-烷基噻吩）聚合物薄膜与共轭长度减少，伴随着增加扭转角。扭曲程度越高的聚合物表现出更短的自旋扩散长度和巨大的自旋混合电导（高达10（21）m（-2）），这归因于结构构象增加的SOC。这为提高自旋电子学应用中有机材料的SOC和自旋注入效率提供了一条途径。
Manipulating spin-orbit coupling (SOC) is a key achievement for spin-orbitronic applications since SOC determines spin-diffusion lengths and spin-to-charge conversion efficiencies. While in most organic semiconductors SOC is inherently very weak due to being composed of primarily light elements, the SOC in conjugated polymer systems is also intimately tied to the polymer's structural conformation and thus may be manipulated. Here we report a modification of SOC in conjugated polymers by altering torsion angle between conjugated units. Spin-pumping experiments are performed on three poly(3-alkylthiophene) polymer films with decreasing conjugation lengths and concomitantly increasing torsion angle. The more twisted polymer exhibits a shorter spin-diffusion length and a giant spin-mixing conductance (up to 10(21) m(-2)), which is attributed to an increased SOC by structural conformation. This work offers a route for enhancing SOC and spin-injection efficiency in organic materials for spintronic applications.