Spin-Peierls化合物的分子设计策略及电操控自旋态研究

当前，分子自旋电子材料在量子调控与量子信息方面备受关注，故而吸引了化学、材料科学和器件物理领域研究者极大兴趣，其中自旋操控是此类材料实现应用的基本途径。而相较于温度、光或磁场，电操控自旋态更灵敏、有效、易于实际应用。迄今为止，电操控自旋态是基于二级Stark效应或电致伸缩效应，需在超高电场下完成，存在电子元件易被电击穿等风险。本项目将探索低电场调控spin-Peierls铁电化合物自旋转换性质以实现自旋电操控目标。我们拟设计合成[R2-Bz-Im-R1][M(mnt)2]（M = Ni、Pd、Pt；mnt2- = maleonitriledithiolate；Im = 咪唑；R1，R2 = 取代基）系列spin-Peierls型铁电化合物，因其兼具强一级Stark效应和机电耦合效应（逆压电效应），两种效应协同可实现低电场操控其自旋态，以期获得实用可控的低能耗自旋电子材料。

Recently, the materials, with the functionality for information processing and storage used in the spintronics devices, have attracted much attention and interest from researchers in chemistry, materials science and device physics. A material has practical application for spintronics only when its spin states are manipulatible. Compared with manipulating spin states using temperature change, irradiation or magnetic field, it is an efficient and more practical method to electrically manipulate spin states. Electrically manipulating spin states have mainly achieved via the second-order Stark effect or electrostriction effect hitherto. However, these strategies need much higher electric field, resulting in several shortcomings, such as the electronic components suffering from a risk of electrical breakdown. In this research proposal, we would explore new pathway of manipulating spin states under low electric field. We will prepare, characterize a series of one-dimensional S = 1/2 spin-Peierls-type ferroelectric compounds, [R2-Bz-Im-R1][M(mnt)2] with M = Ni, Pd, Pt; mnt2- = maleonitriledithiolate; Im = imidazole; R1, R2 = substituent groups, which are used for the study of electrically manipulating spin states. Since a polar ferroelectric crystal exhibits the first-order Stark effect, being much stronger than the second-order Stark effect, thus, manipulating spin states in such a crystal is probably realized under lower electric field. Additionally, the molecule ferroelectric crystal shows excellent compressibility and inverse piezoelectric effect simultaneously, and its spin-Peierls transition nature is tunable by pressure because, on the one hand, the pressure promotes the transition from the gapless to spin-gap states in a spin-Peierls system. On the other hand, the strain/stress achieved via mechanoelectric coupling can be used for tuning the spin transition nature of spin-Peierls-type ferroelectric crystal. To combine the first-order Stark and mechanoelectric coupling effects, manipulating spin states is probably realized in a spin-Peierls-type ferroelectric system under lower electric field. The study in this proposal will open a new pathway for achieving spintronics materials with low energy consumption.