Related Experiment Video
Updated: Jun 20, 2026

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
Optical access of spin-polarized excited states in Cs(PbMgZnCd)Br3 nanocrystals
Yu Zhang1,2, Haidi Liu1,2, Shuchun Zhang1,2
1Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
Abstract:
The interplay of slow spin relaxation (long τS) and fast radiative recombination (short τR) 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 τS (59.8 ps) and short τR (3.4 ns) in the colloidal nanocrystals of high-entropy perovskites, Cs(PbMgZnCd)Br3, which enables the optical access and spin manipulation of excited states at room temperature. The incorporation of non-Pb metals spatially separates the [PbBr6]4- 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 [PbBr6]4- lattice is significantly enhanced in high-entropy structures, which enlarges the Rashba spin splitting and consequently prolongs τS 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)Br3. 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.
Related Concept Videos
Atomic Nuclei: Nuclear Spin State Overview
NMR Spectroscopy: Spin–Spin Coupling
Atomic Nuclei: Nuclear Relaxation Processes
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
Atomic Nuclei: Magnetic Resonance

