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Mechanistic Insight into Tunable Spin Relaxation in Two-Dimensional Type-II Ligand-Perovskite Heterostructures
Ashish Soni1, Cheng Yang1, Yu-Ting Yang1,2
1Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
Journal of the American Chemical Society
|October 29, 2025
Summary
Engineered 2D perovskites with type-II heterostructures significantly extend spin lifetimes, overcoming limitations from spin-orbit coupling and phonon scattering for spintronics. This ligand engineering approach enhances spin properties in advanced quantum applications.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Quantum Optics
Background:
- Two-dimensional (2D) metal-halide perovskites offer unique spin-dependent optical properties crucial for spintronics and quantum technologies.
- Short spin lifetimes in 2D perovskites, particularly n=1, are attributed to strong spin-orbit coupling (SOC), electron-hole exchange, and phonon scattering.
Purpose of the Study:
- To overcome the limitations of short spin lifetimes in 2D perovskites.
- To demonstrate the efficacy of type-II ligand-perovskite heterostructures in extending spin lifetimes.
- To establish a structural design framework for manipulating spin dynamics in 2D perovskites.
Main Methods:
- Fabrication of type-II ligand-perovskite heterostructures, specifically (4Tm)2PbI4 and (4TCNm)2PbI4.
- Characterization of spin lifetimes using temperature- and fluence-dependent measurements.
- Analysis of spin relaxation mechanisms, including Bir-Aronov-Pikus (BAP), Elliott-Yafet (EY), and D'yakonov-Perel (DP).
Main Results:
- Type-II heterostructures significantly extended spin lifetimes compared to type-I (PEA)2PbI4 (0.29 ps).
- (4Tm)2PbI4 exhibited a spin lifetime of ~6.37 ps, dominated by Elliott-Yafet (EY) relaxation.
- (4TCNm)2PbI4 showed a spin lifetime of ~18.47 ps at room temperature, extending to ~126.81 ps at 5 K, with D'yakonov-Perel (DP) dominated relaxation.
Conclusions:
- Type-II ligand engineering effectively reduces electron-hole overlap and exciton binding energy, mitigating BAP spin relaxation.
- Spatial charge separation in heterostructures is key to enhancing spin lifetimes.
- The study provides a rational design strategy for tailoring spin dynamics in 2D perovskites for advanced optoelectronic and spintronic applications.
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