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arXiv · 2104.02970

Switchable Rashba Anisotropy in Two-dimensional Hybrid Organic-Inorganic Perovskite by Hybrid Improper Ferroelectricity

Fei Wang·Heng Gao·Coen de Graaf·Josep M. Poblet·Branton J. Campbell·Alessandro Stroppa
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Abstract

Two-dimensional (2D) hybrid organic-inorganic perovskites (HOIPs) are introducing new directions in the 2D materials landscape. The coexistence of ferroelectricity and spin-orbit interactions play a key role in their optoelectronic properties. We perform a detailed study on a recently synthesized ferroelectric 2D-HOIP, (AMP)PbI$_4$ (AMP = 4-aminomethyl-piperidinium). The calculated polarization and Rashba parameter are in excellent agreement with experimental values. We report a striking new effect, i.e., an extraordinarily large Rashba anisotropy that is tunable by ferroelectric polarization: as polarization is reversed, not only the spin texture chirality is inverted, but also the major and minor axes of the Rashba anisotropy ellipse in k-space are interchanged - a pseudo rotation. A $k \cdot p$ model Hamiltonian and symmetry-mode analysis reveal a quadrilinear coupling between the cation-rotation modes responsible for the Rashba ellipse pseudo-rotation, the framework rotation, and the polarization. These findings may provide new avenues for spin-optoelectronic devices such as spin valves or spin FETs.

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Fei Wang, Heng Gao, Coen de Graaf, Josep M. Poblet, Branton J. Campbell, Alessandro Stroppa. 2021-04-07. Switchable Rashba Anisotropy in Two-dimensional Hybrid Organic-Inorganic Perovskite by Hybrid Improper Ferroelectricity. https://doi.org/10.1038/s41524-020-00450-z

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