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Kinetically Controlled Structural Transitions in Layered Halide-Based Perovskites: An Approach to Modulate Spin Splitting
Journal of the American Chemical Society ( IF 15.0 ) Pub Date : 2022-08-11 , DOI: 10.1021/jacs.2c05574
Yi Xie 1, 2 , Ruyi Song 3 , Akash Singh 1, 2 , Manoj K Jana 1 , Volker Blum 1, 3 , David B Mitzi 1, 3
Affiliation  

Two-dimensional hybrid organic–inorganic perovskite (HOIP) semiconductors with pronounced spin splitting, mediated by strong spin–orbit coupling and inversion symmetry breaking, offer the potential for spin manipulation in future spintronic applications. However, HOIPs exhibiting significant conduction/valence band splitting are still relatively rare, given the generally observed preference for (near)centrosymmetric inorganic (especially lead-iodide-based) sublattices, and few approaches are available to control this symmetry breaking within a given HOIP. Here, we demonstrate, using (S-2-MeBA)2PbI4 (S-2-MeBA = (S)-(−)-2-methylbutylammonium) as an example, that a temperature-induced structural transition (at ∼180 K) serves to change the degree of chirality transfer to and inversion symmetry breaking within the inorganic layer, thereby enabling modulation of HOIP structural and electronic properties. The cooling rate is shown to dictate whether the structural transition occurs─i.e., slow cooling induces the transition while rapid quenching inhibits it. Ultrafast calorimetry indicates a minute-scale structural relaxation time at the transition temperature, while quenching to lower temperatures allows for effectively locking in the metastable room-temperature phase, thus enabling kinetic control over switching between distinct states with different degrees of structural distortions within the inorganic layers at these temperatures. Density functional theory further highlights that the low-temperature phase of (S-2-MeBA)2PbI4 shows more significant spin splitting relative to the room-temperature phase. Our work opens a new pathway to use kinetic control of crystal-to-crystal transitions and thermal cycling to modulate spin splitting in HOIPs for future spintronic applications, and further points to using such “sluggish” phase transitions for switching and control over other physical phenomena, particularly those relying on structural distortions and lattice symmetry.

中文翻译:

层状卤化物基钙钛矿的动力学控制结构转变:一种调节自旋分裂的方法

二维杂化有机-无机钙钛矿(HOIP)半导体具有明显的自旋分裂,由强自旋轨道耦合和反转对称破坏介导,为未来自旋电子应用中的自旋操纵提供了潜力。然而,考虑到普遍观察到的对(近)中心对称无机(尤其是碘化铅基)亚晶格的偏好,表现出显着导带/价带分裂的 HOIP 仍然相对罕见,并且很少有方法可以控制给定 HOIP 内的这种对称性破坏. 在这里,我们演示,使用 (S-2-MeBA) 2 PbI 4(S-2-MeBA = (S)-(-)-2-甲基丁基铵)作为例子,温度诱导的结构转变(在~180 K)用于改变手性转移的程度和反转对称性破坏无机层,从而能够调节HOIP结构和电子特性。冷却速度表明结构转变是否发生——即,缓慢冷却诱导转变,而快速淬火抑制转变。超快量热法表明在转变温度下存在微小的结构弛豫时间,而淬火至较低温度允许有效地锁定在亚稳态室温相中,从而能够对具有不同程度结构扭曲的不同状态之间的切换进行动力学控制。在这些温度下的层。2 PbI 4相对于室温相显示出更显着的自旋分裂。我们的工作开辟了一条新途径,使用晶体到晶体转变和热循环的动力学控制来调节 HOIP 中的自旋分裂,以用于未来的自旋电子应用,并进一步指出使用这种“缓慢”的相变来切换和控制其他物理现象,尤其是那些依赖于结构扭曲和晶格对称的。
更新日期:2022-08-11
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