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

Abstract

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.

Structural chemistry of layered lead halide perovskites containing single octahedral layers

“…The structures observed in these compounds are obviously dictated by the total energetics of the system, which will depend on a subtle interplay and co-operation between the molecular moieties and the inorganic framework. An interesting recent example (Park et al, 2019) which leads to unusual physical properties (Wang et al, 2020) is that of [C 6 H 16 N 2 ]PbI 4 (1939809 and 1831525, Table 4), which exhibits an order-disorder transition of the 4-aminopiperidine, but this hardly changes the distortions within the [PbI 4 ] 1 layer itself. In this section, we will consider structural trends across this family of compounds, and we highlight a few interesting cases of interlayer cation influence on the overall structure.…”

Spin-Current Modulation in Hexagonal Buckled ZnTe and CdTe Monolayers for Self-Powered Flexible-Piezo-Spintronic Devices

“…The spin degree of freedom (spin-up and spin-down) of an electron is an intrinsic property and relatively easier to manipulate in the presence of a magnetic field as compared to the motion of the electronic charge. Recent experiments have demonstrated the usage of the spin degree of freedom to store and manipulate data that can be the fastest and effective way to store a large amount of data for a long time and can pave the way for next-generation high-speed quantum information devices. − The 21st century witnessed significant technological advancements in electronics, data storage devices, quantum computing (spintronics/valleytronics), etc. − Spintronics utilizes the spin of electrons to gather and store information that leads to the next-generation data storage devices, magnetic sensor applications, etc. The spintronic device consists mainly of two ferromagnetic electrodes in which one acts as an electron emitter with a particular spin direction and the other acts as a collector or spin-filter of the emitted electron and a semiconducting channel. , However, the development of a very efficient, low-power spintronic device is confronted with many challenges such as high magnetic anisotropy, long spin lifetime, modulation of spin current, and temperature-dependent spin properties .…”

Structural descriptor for enhanced spin-splitting in 2D hybrid perovskites

“…Additionally, a complex interplay of electrostatic requirements, steric effects, intermolecular interactions, and hydrogen-bonding associated with the organic cations engenders intricate distortions within the inorganic layers that have been previously correlated with exciton energy shifts 17,18 and exciton self-trapping 19 . When such distortions break the inversion symmetry of the inorganic layer, Rashba/Dresselhaus spin-splitting can emerge due to spin-orbit coupling (SOC) [20][21][22][23][24] . Rashba/Dresselhaus spinsplitting is a relativistic quantum phenomenon in condensed matter that leads to important physical manifestations for emerging spin-orbitronic devices, including intrinsic spin-Hall effect 25 , gate-controlled spin precession 26 , (inverse) spin galvanic effects, photogalvanic effects 27 , and chiroptic effects 28 , that rely on SOC-mediated manipulation of the spin degrees of freedom by electrical, optical, or magnetic means 22,25 .…”