Meliakov Sergey R, Zhukov Evgeny A, Belykh Vasilii V, Nestoklon Mikhail O, Kolobkova Elena V, Kuznetsova Maria S, Bayer Manfred, Yakovlev Dmitri R
P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Moscow, Russia.
Experimentelle Physik 2, Technische Universität Dortmund, 44227 Dortmund, Germany.
Nanoscale. 2025 Mar 13;17(11):6522-6529. doi: 10.1039/d4nr04602a.
The Landé -factor of charge carriers is a key parameter in spin physics controlling spin polarization and spin dynamics. In turn, it delivers information about the electronic band structure in the vicinity of the band gap and its modification in nanocrystals provided by strong carrier confinement. The coherent spin dynamics of electrons and holes are investigated in CsPbI perovskite nanocrystals with sizes varied from 4 to 16 nm by means of time-resolved Faraday ellipticity at the temperature of 6 K. The Landé -factors of the charge carriers are evaluated through the Larmor spin precession in magnetic fields up to 430 mT across the spectral range from 1.69 to 2.25 eV, provided by variation of the nanocrystal size. The spectral dependence of the electron -factor follows the model predictions when accounting for the mixing of the electronic bands with increasing confinement resulting from a decrease of the nanocrystal size. The spectral dependence of the hole -factor, changing from -0.19 to +1.69, is considerably stronger than expected from the model. We analyze several mechanisms and conclude that none of them can be responsible for this difference. The renormalizations of the electron and hole -factors roughly compensate each other, providing spectral independence for the bright exciton -factor with a value of about +2.2.
电荷载流子的朗德因子是自旋物理学中控制自旋极化和自旋动力学的关键参数。反过来，它提供了有关带隙附近电子能带结构及其在强载流子限制作用下在纳米晶体中变化的信息。通过在6K温度下的时间分辨法拉第椭圆率，研究了尺寸从4到16nm变化的CsPbI钙钛矿纳米晶体中电子和空穴的相干自旋动力学。通过在高达430mT的磁场中，利用纳米晶体尺寸变化所提供的1.69至2.25eV光谱范围内的拉莫尔自旋进动，来评估电荷载流子的朗德因子。当考虑到随着纳米晶体尺寸减小导致的限制增加而引起的电子能带混合时，电子因子的光谱依赖性遵循模型预测。空穴因子的光谱依赖性从-0.1到 +1.69变化，比模型预期的要强得多。我们分析了几种机制并得出结论，没有一种机制能解释这种差异。电子和空穴因子的重整化大致相互补偿，使得明亮激子因子在光谱上具有约 +2.2的独立性。
