Optical access of spin-polarized excited states in Cs(PbMgZnCd)Br<sub>3</sub> nanocrystals.

Zhang, Yu; Liu, Haidi; Zhang, Shuchun; Yang, Zhengwei; Chang, Qingda; Xu, Lixin; Yan, Yongli; Zhang, Chuang · Nat Commun · 2026

basic_science · Level V

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Abstract

The interplay of slow spin relaxation (long τ<sub>S</sub>) and fast radiative recombination (short τ<sub>R</sub>) is essential for using spin-polarized excited states in lead halide perovskites towards spintronics and quantum-optics technologies. Herein, we report on the observation of simultaneously long τ<sub>S</sub> (59.8 ps) and short τ<sub>R</sub> (3.4 ns) in the colloidal nanocrystals of high-entropy perovskites, Cs(PbMgZnCd)Br<sub>3</sub>, which enables the optical access and spin manipulation of excited states at room temperature. The incorporation of non-Pb metals spatially separates the [PbBr<sub>6</sub>]<sup>4-</sup> framework into smaller domains below the Bohr radius of excitons, and the size confinement leads to blue-shifted bright photoluminescence from short-lived photoexcitation species. Moreover, the distortion of [PbBr<sub>6</sub>]<sup>4-</sup> lattice is significantly enhanced in high-entropy structures, which enlarges the Rashba spin splitting and consequently prolongs τ<sub>S</sub> over an order of magnitude. Optical write-in and read-out of spin states via circularly polarized light are achieved for both photoluminescence and amplified spontaneous emission from Cs(PbMgZnCd)Br<sub>3</sub>. Optical Hanle effect is demonstrated and allows for very efficient spin manipulation (positive/negative polarizations ~25.8%) under a perpendicular magnetic field, showing the great potential of high-entropy perovskites for opto-spintronic applications.