Switchable Rashba anisotropy in layered hybrid organic–inorganic perovskite by hybrid improper ferroelectricity

Identifier:  imarina:9138947

Handle: https://hdl.handle.net/20.500.11797/imarina9138947

Authors:  Wang, Fei; Gao, Heng; de Graaf, Coen; Poblet, Josep M; Campbell, Branton J; Stroppa, Alessandro

Abstract:
© 2020, The Author(s). Hybrid organic–inorganic perovskites (HOIPs) are introducing exotic directions in the photovoltaic materials landscape. The coexistence of inversion symmetry breaking and spin–orbit interactions play a key role in their optoelectronic properties. We perform a detailed study on a recently synthesized ferroelectric layered HOIP, (AMP)PbI4 (AMP = 4-aminomethyl-piperidinium). The calculated polarization and Rashba parameters are in excellent agreement with experimental values. Moreover, we report a striking 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·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 different avenues for spin-optoelectronic devices such as spin valves or spin FETs.