Pham Minh T, Amerling Eric, Luong Hoang M, Pham Huy T, Larsen George K, Whittaker-Brooks Luisa, Nguyen Tho D
Department of Physics & Astronomy, University of Georgia, Athens, GA, 30602, USA.
Department of Chemistry, University of Utah, Salt Lake City, UT, 84112, USA.
Sci Rep. 2020 Mar 18;10(1):4964. doi: 10.1038/s41598-020-61768-8.
We studied spin dynamics of charge carriers in the superlattice-like Ruddlesden-Popper hybrid lead iodide perovskite semiconductors, 2D (BA)(MA)PbI (with MA = CHNH, and BA = CH(CH)NH), and 3D MAPbI using the magnetic field effect (MFE) on conductivity and electroluminescence in their light emitting diodes (LEDs) at cryogenic temperatures. The semiconductors with distinct structural/bulk inversion symmetry breaking, when combined with colossal intrinsic spin-orbit coupling (SOC), theoretically give rise to giant Rashba-type SOC. We found that the magneto-conductance (MC) magnitude increases monotonically with the emission intensity and saturates at ≈0.05% and 0.11% for the MAPbI and (BA)(MA)PbI, respectively. The magneto-electroluminescence (MEL) response with similar line shapes as the MC response has a significantly larger magnitude, and essentially stays constant at ≈0.22% and ≈0.20% for MAPbI and (BA)(MA)PbI, respectively. The sign and magnitude of the MC and MEL responses can be quantitatively explained in the framework of the Δg-based excitonic model using rate equations. Remarkably, the width of the MEL response in those materials linearly increases with increasing the applied electric field, where the Rashba coefficient in (BA)(MA)PbI is estimated to be about 7 times larger than that in MAPbI. Our studies might have significant impact on future development of electrically-controlled spin logic devices via Rashba-like effects.
我们研究了超晶格状的Ruddlesden-Popper混合碘化铅钙钛矿半导体中电荷载流子的自旋动力学，即二维（BA）（MA）PbI（其中MA = CH₃NH₃，BA = C₄H₉NH₃）和三维MAPbI，通过在低温下利用磁场效应（MFE）对其发光二极管（LED）的电导率和电致发光进行研究。这些具有明显结构/体反转对称性破缺的半导体，与巨大的本征自旋-轨道耦合（SOC）相结合，理论上会产生巨大的Rashba型SOC。我们发现，磁电导（MC）幅度随发射强度单调增加，对于MAPbI和（BA）（MA）PbI，分别在≈0.05%和0.11%时达到饱和。与MC响应具有相似线形的磁电致发光（MEL）响应幅度明显更大，对于MAPbI和（BA）（MA）PbI，分别基本保持在≈0.22%和≈0.20%不变。MC和MEL响应的符号和幅度可以在基于Δg的激子模型框架内使用速率方程进行定量解释。值得注意的是，这些材料中MEL响应的宽度随施加电场的增加而线性增加，其中（BA）（MA）PbI中的Rashba系数估计比MAPbI中的大约大7倍。我们的研究可能会对通过类似Rashba效应的电控自旋逻辑器件的未来发展产生重大影响。
