利用分子与磁性电极界面的重构等原子构型增强磁电阻

项目名称： 利用分子与磁性电极界面的重构等原子构型增强磁电阻

项目编号： No.11474145

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 石兴强

作者单位： 南方科技大学

项目金额： 90万元

中文摘要： 近年的研究表明分子吸附会引起金属密堆表面发生重构，如富勒烯、硫醇盐、石墨烯等吸附引起的铜、金、铂等表面重构；这些研究关注非磁性电极表面，已证明对分子电子学的研究有重要意义。本项目将把吸附引起的重构研究拓展到分子自旋电子学中，研究分子与磁性金属、半金属、合金等的组合体系。我们的预研究表明分子吸附引起的磁性表面重构会增强分子与电极的自旋依赖轨道杂化，这使得同时提高电导率和磁电阻比率成为可能；而这两个参数同时提高对于自旋器件进一步小型化至关重要。此外范德瓦尔斯（vdW）力对于成功描述界面的成键性质（进而确定磁性质）很重要。所以本项目将采用包含vdW力的第一性原理计算模拟并结合STM和LEED实验来系统研究多个典型分子在多种磁性表面的吸附和重构，及改良界面原子构型对自旋注入和磁电阻的增强作用。本项目将深入揭示界面接触原子细节与自旋极化增强的关系，并在此基础上设计兼具大磁阻率和低电阻的分子自旋器件。

中文关键词： 表面吸附；表面重构；自旋注入；第一性原理计算；扫描隧道显微术

英文摘要： Recent studies show that molecular adsorption can induce reconstruction of close-packed metal surfaces, such as the reconstructions of Cu, Au and Pt surfaces with adsorption of fullerene, thiolate and graphene; these studies focused on nonmagnetic electrodes and are of great importance for molecular electronics studies. This project will extend adsorption induced surface reconstruction to molecular spintronics via detailed study of the interaction of molecules with ferromagnetic and antiferromagnetic metals, half-metals and alloys, etc. Our pre-researches show that magnetic surface reconstruction induced by molecular adsorption can enhance the spin-dependent hybridization at molecule-electrode interface, which makes simultaneously increase magnetoresistance (MR) and conductance possible, and increase these two parameters simultaneously are essential for further miniaturization of spintronic-devices. In addition, van der Waals (vdW) interactions are very important for the determination of interface bonding mechanism and hence important for the determination of magnetic properties. So this project will adopt DFT-based simulations with vdW interaction included and combine with STM and LEED experiments to study adsorption and reconstruction, and their relations with molecular spin-polarization and MR enhancement, for typical molecules on various types of magnetic surfaces. This project will reveal the relation between spin-polarization enhancement and interface atomic detail contacts, and design spintronic-devices with both larger MR and higher conductance.

英文关键词： surface adsorption;surface reconstruction;spin injection;DFT simulations;STM