Strong spin-orbit coupling inducing Autler-Townes effect in lead halide perovskite nanocrystals

• Published in: Nature communications Vol. 12; no. 1; p. 3026
• Main Authors: Yumoto, Go, Hirori, Hideki, Sekiguchi, Fumiya, Sato, Ryota, Saruyama, Masaki, Teranishi, Toshiharu, Kanemitsu, Yoshihiko
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 21.05.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 639/301/119/1000; 639/766/400/385; Coherent light; Controllability; Crossovers; Cryogenic temperature; Crystals; Dipole moments; Excitons; Humanities and Social Sciences; I.R. radiation; Lead compounds; Metal halides; multidisciplinary; Nanocrystals; Optical control; Perovskites; Room temperature; Science; Science (multidisciplinary); Spin-orbit interactions; Splitting; Stability; Stark effect; Wavelengths
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-23291-w

Manipulation of excitons via coherent light-matter interaction is a promising approach for quantum state engineering and ultrafast optical modulation. Various excitation pathways in the excitonic multilevel systems provide controllability more efficient than that in the two-level system. However, these control schemes have been restricted to limited control-light wavelengths and cryogenic temperatures. Here, we report that lead halide perovskites can lift these restrictions owing to their multiband structure induced by strong spin-orbit coupling. Using CsPbBr 3 perovskite nanocrystals, we observe an anomalous enhancement of the exciton energy shift at room temperature with increasing control-light wavelength from the visible to near-infrared region. The enhancement occurs because the interconduction band transitions between spin-orbit split states have large dipole moments and induce a crossover from the two-level optical Stark effect to the three-level Autler-Townes effect. Our finding establishes a basis for efficient coherent optical manipulation of excitons utilizing energy states with large spin-orbit splitting. Here, Yumoto et al. demonstrate that for a halide perovskite with large spin-orbit splitting the optical Stark effect can give way to a three level Autler-Townes effect in the near-infrared region. The multiband nature of the effect potentially allows for further optical control over quantum states.