Precision engineering chiral interfaces for efficient spin injection in metal halide heterostructures.

Xiao, Jin; Li, Yang; Liu, Yanan; Li, Jing; Fang, Li; Zheng, Haofeng; Wang, Yanlong; Liu, Qi et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Precise control of interfaces is crucial for spin generation, transport, and detection in opto-spintronics. However, the interface engineering for efficient spin injection remains a significant challenge. Here, we synthesized a helical structure of PbI<sub>2</sub> (R-PbI<sub>2</sub>) via an interfacial chirality-induced growth approach at the heterostructure interface. This few-nanometer-thick R-PbI<sub>2</sub> layer shows a lower lattice mismatch with both the adjacent R-NEAPbI<sub>3</sub> (R-NEA refers to R-1-(1-naphtyl)ethylamine) and PbI<sub>2</sub> layers, and leads to an optimal chiral interface in the chiral heterostructure with minimized residual strain and defect density. Combined with circularly polarized pump-probe spectroscopic and spin-photovoltaic measurements, our chiral heterostructure interface contributes a spin-injection efficiency up to 68%, thus leading to a degree of polarization of 29% in photocurrent. The precise synthesis of a chiral interface offers a promising route to manipulate spin dynamics and achieve a high degree of spin polarization required for advanced opto-spintronic applications.