薄膜
铁磁性
磁化
自旋(空气动力学)
克尔效应
脉冲激光沉积
激子
带隙
半导体
密度泛函理论
作者
David Giovanni,Hong Ma,Julianto Chua,Michael Grätzel,Ramamoorthy Ramesh,Subodh Mhaisalkar,Nripan Mathews,Tze Chien Sum
出处
期刊:Nano Letters
[American Chemical Society]
日期:2015-02-09
卷期号:15 (3): 1553-1558
被引量:130
摘要
Low-temperature solution-processed organic-inorganic halide perovskite CH3NH3PbI3 has demonstrated great potential for photovoltaics and light-emitting devices. Recent discoveries of long ambipolar carrier diffusion lengths and the prediction of the Rashba effect in CH3NH3PbI3, that possesses large spin-orbit coupling, also point to a novel semiconductor system with highly promising properties for spin-based applications. Through circular pump-probe measurements, we demonstrate that highly polarized electrons of total angular momentum (J) with an initial degree of polarization Pini ∼90% (i.e., -30% degree of electron spin polarization) can be photogenerated in perovskites. Time-resolved Faraday rotation measurements reveal photoinduced Faraday rotation as large as 10°/μm at 200 K (at wavelength λ = 750 nm) from an ultrathin 70 nm film. These spin polarized carrier populations generated within the polycrystalline perovskite films, relax via intraband carrier spin-flip through the Elliot-Yafet mechanism. Through a simple two-level model, we elucidate the electron spin relaxation lifetime to be ∼7 ps and that of the hole is ∼1 ps. Our work highlights the potential of CH3NH3PbI3 as a new candidate for ultrafast spin switches in spintronics applications.
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