Room-temperature electrically switchable spin–valley coupling in a van der Waals ferroelectric halide perovskite with persistent spin helix
Room-temperature electrically switchable spin–valley coupling in a van der Waals ferroelectric halide perovskite with persistent spin helix
复制标题
DOI：
10.1038/s41566-022-01016-9
复制
发表时间：
2022-06
期刊：
影响因子：
35
通讯作者：
Lifu Zhang;Jie Jiang;Christian Multunas;Chen Ming;Zhizhong Chen;Yang Hu;Zonghuan Lu;S. Pendse;Ru Jia;M. Chandra;Yi-Yang Sun-;T. Lu;Y. Ping;R. Sundararaman;Jian Shi
中科院分区：
文献类型：
--
作者：
Lifu Zhang;Jie Jiang;Christian Multunas;Chen Ming;Zhizhong Chen;Yang Hu;Zonghuan Lu;S. Pendse;Ru Jia;M. Chandra;Yi-Yang Sun-;T. Lu;Y. Ping;R. Sundararaman;Jian Shi
自旋电子器件通过利用自旋自由度，预计在能量效率和操作速度方面优于基于电荷的器件。利用电场在室温下控制自旋已经进行了几十年。导致这方面进展缓慢的一个主要障碍是有效控制和强自旋弛豫之间的困境。例如，在具有强自旋-轨道耦合的Rashba/Dresselhaus材料中，尽管内部磁场可以足够大以有效地控制自旋进动，但通常，由于Dyakonov-Perel散射，自旋弛豫时间变得非常短。为了解决这个问题，在SU（2）对称性的系统中提出了一种持久的自旋螺旋。在这里，我们展示了在有机-无机混合铁电卤化物钙钛矿中发现持久的自旋螺旋，其层状性质使其本质上像量子阱。我们证明了自旋极化能带结构在室温下可以通过本征铁电场进行切换。我们揭示了谷自旋耦合通过圆形光电效应在单晶体晶体。有利的短自旋螺旋波长（比III-V材料短三个数量级）、室温操作和非挥发性使混合钙钛矿成为理解自旋调谐自旋动力学的理想平台，以设计可以解决控制弛豫困境的实用自旋电子材料和器件。
Spintronic devices, by harnessing the spin degree of freedom, are expected to outperform charge-based devices in terms of energy efficiency and speed of operation. The use of an electric field to control spin at room temperature has been pursued for decades. A major hurdle that has contributed to the slow progress in this regard is the dilemma between effective control and strong spin relaxation. For example, in a Rashba/Dresselhaus material with strong spin–orbit coupling, although the internal magnetic field could be substantial enough to effectively control spin precession, often, the spin-relaxation time becomes extremely short as a consequence of Dyakonov–Perel scattering. To address this, a persistent spin helix has been proposed in systems with SU(2) symmetry. Here we show the discovery of the persistent spin helix in an organic–inorganic hybrid ferroelectric halide perovskite whose layered nature makes it intrinsically like a quantum well. We demonstrate that the spin-polarized band structure is switchable at room temperature via an intrinsic ferroelectric field. We reveal valley–spin coupling through a circular photogalvanic effect in single-crystalline bulk crystals. The favoured short spin helix wavelength (three orders of magnitude shorter than in III–V materials), room-temperature operation and non-volatility make the hybrid perovskite an ideal platform for understanding symmetry-tuned spin dynamics, towards designing practical spintronic materials and devices that can resolve the control-relaxation dilemma.