Spin-Electric Coupling with Anisotropy-Induced Vanishment and Enhancement in Molecular Ferroelectrics

Abstract

Manipulating quantum properties by electric fields using spin-electric coupling (SEC) effects promises spatial addressability. While several studies about inorganic materials showing the SEC functionality have been reported, the vastly tunable crystal structures of molecular ferroelectrics provide a range of rationally designable materials yet to be exploited. In this work, Mn2+-doped molecular ferroelectrics are chosen to experimentally demonstrate the feasibility of achieving the quantum coherent SEC effect in molecular ferroelectrics for the first time. The electric field pulse applied between Hahn-echo pulses in electron paramagnetic resonance (EPR) experiments causes controllable phase shifts via manipulating of the zero-field splitting (ZFS) of the Mn­(II) ions. Detailed investigations of the aMn crystal showed unexpected SEC vanishment and enhancement at different crystal orientations, which were elucidated by studying the spin Hamiltonian and magnetic anisotropy. With the enhanced SEC efficiency being achieved (0.68 Hz m/V), this work discovers an emerging material library of molecular ferroelectrics to implement coherent quantum control with selective and tunable SEC effects toward highly scalable quantum gates.

Targeted regulation and optimization of multifunctional phase transition materials by novel void occupancy engineering

“…In recent years, significant progress has been made in the design and regulation of molecular-based phase transition materials. 18–33 It is worth noting that the “quasi-spherical theory” aims to reduce molecular symmetry and generate oriented molecular dipole moment by introducing specific chemical groups into spherical cations, which is expected to produce a low-symmetric polar crystal structure and even exhibit ferroelectric phase transition behavior. 34,35 Hua et al modified the [(CH 3 ) 4 N] + cation with a halogen (F, Cl, Br, and I) to enhance the phase transition temperature and successfully obtained a hybrid perovskite ferroelectric [(CH 3 ) 3 NCH 2 I]PbI 3 .…”

Structural Diversity and Tunable Ferroelectricity in a Family of Hybrid Perovskites: AM(NO3)3

“…As one of the most important properties of perovskite materials, ferroelectricity was also realized in hybrid perovskites. These hybrid perovskites offer the opportunity to combine ferroelectricity with other properties, which gives rise to novel properties, such as magnetoferroelectric properties, photoferroelectric properties, and semiconducting ferroelectric properties. − The last decade has witnessed the rapid renaissance of hybrid perovskite materials because of their easy process, light weight, mechanical flexibility, and even excellent ferroelectric properties. Although HOIPs can have a diverse range of compositions, including halides, formates, cyanides, dicyanamides, azides, and dicyanometallates, ferroelectricity is realized mainly in alkaline metal/NH 4 + halides and metal formates.…”

“…Although HOIPs can have a diverse range of compositions, including halides, formates, cyanides, dicyanamides, azides, and dicyanometallates, ferroelectricity is realized mainly in alkaline metal/NH 4 + halides and metal formates. For instance, caged organic–inorganic hybrid ferroelectrics, [NH 4 ]­[M­(HCOO) 3 ] (M = Mn, Fe, Co, Ni, and Zn), have been successfully designed, showing extraordinary magneto-electric coupling and/or spin-electric coupling effects in a wide temperature range . However, the Curie temperature ( T c ), as a fundamental property of the ferroelectric material, is much lower than room temperature.…”

Fluorination Enables Dual Ferroelectricity in Both Solid- and Liquid-Crystal Phases

“…Ferroelectricity describes switchable spontaneous electrical polarization that can exist in polar substances of either solid or liquid crystals. − The history of ferroelectrics began with the disclosure of a peculiar dielectric behavior of solid crystal (SC) Rochelle salt in 1920, and in the following century, various types of ferroelectric solids emerged, including inorganic crystals or ceramics, , molecular crystals, − and polymers. , Their switchable polarization features with excellent electrical, mechanical, and optical properties have been extensively studied and widely used in memory elements, capacitors, transducers, actuators, and sensors. , The connection between ferroelectricity and liquid crystals (LCs) started in 1975 with the discovery of the first ferroelectric LC DOBAMBC . Ferroelectric LCs have unique application advantages in display and optoelectronics due to their exceptionally fast electro-optical response and the special photoelectric effect. − For a long time, compared to other types of LC phases with D ∞h symmetry, the chiral smectic LC phase was thought to exhibit ferroelectricity because of the C 2 -symmetric polarization vector perpendicular to both the director and the molecular layer direction. − Subversively, in recent years, ferroelectricity has also been experimentally proved in the nematic LCs with C ∞v symmetry, breaking the conventional thinking of ferroelectric LCs and opening a new chapter in condensed matter science and related applications. − The broken head-to-tail symmetry of two permissible director orientations in such a nematic LC system enables the molecular dipoles to spontaneously orient to a preferred direction, generating macroscopic polarization. ,− Liquid crystals can be generated by heating some organic solid crystals .…”