Composition gradient-enabled circular photogalvanic effect in inogranic halide perovskites

Inversion symmetry breaking could lead to the creation of a Rashba–Dresselhauls magnetic field, which plays the key role in spintronic devices. In this work, we propose and develop a composition gradient engineering approach that breaks inversion symmetry into inorganic halide perovskites with strong spin–orbit coupling. We synthesize epitaxial CsPbBr xCl(3− x) with Br/Cl composition gradient by a two-step chemical vapor deposition approach. Through optoelectronic measurements, we show the presence of circular photogalvanic effects (CPGEs), evidencing a Rashba-like spin polarized band structure. By spatially resolved photoluminescence spectra, we find that the observed CPGE is likely a cumulative result of inversion symmetry-broken interfaces featured by abrupt and stepwise composition gradient between the pristine and separated daughter phases. Our work suggests an avenue in engineering the spintronic property of halide perovskites for information processing.

反转对称性破缺可能导致产生拉什巴 - 德雷斯尔豪斯磁场，该磁场在自旋电子器件中起着关键作用。在这项工作中，我们提出并开发了一种成分梯度工程方法，该方法将具有强自旋 - 轨道耦合的无机卤化物钙钛矿的反转对称性打破。我们通过两步化学气相沉积法合成了具有溴/氯成分梯度的外延CsPbBrₓCl₍₃ - ₓ₎。通过光电测量，我们证明了圆光电效应（CPGEs）的存在，这证明了类拉什巴自旋极化能带结构的存在。通过空间分辨光致发光光谱，我们发现观察到的CPGE可能是原始相和分离相之间由突变和逐步成分梯度所表征的反转对称性破缺界面的累积结果。我们的工作为调控卤化物钙钛矿的自旋电子特性以用于信息处理提供了一种途径。