携轨道角动量螺旋电子显微方法的拓展及在材料表征中应用的研究

项目名称： 携轨道角动量螺旋电子显微方法的拓展及在材料表征中应用的研究

项目编号： No.11474249

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： 田鹤

作者单位： 浙江大学

项目金额： 80万元

中文摘要： 螺旋电子束是一种具有螺旋相位，携带轨道角动量的电子束。我们先期取得的初步成果中，利用螺旋电子束实现材料磁性表征的能力已经得到首次展示，证明螺旋电子束具有原子尺度磁性成像的潜力。目前为止，还没有任何方法可以在原子尺度实现材料内部局域磁性的测量。螺旋电子束电子显微学作为新型研究领域，由于其具有非常广泛的应用前景，已受到国内外物理、材料等领域科学家的广泛关注。本项目将契合此领域国际发展的趋势，利用先进的透射电镜技术，发展螺旋电子束原子级分辨的磁性自旋结构成像的方法，应用于自旋电子器件的自旋特性的表征，如拓扑绝缘体等。同样，通过本项目，拟利用螺旋电子束与材料间轨道角动量传递的特性，实现纳米尺度材料的束缚与操控。这将有助于实现真正意义上的纳米组装，及打造更小的电子芯片和纳米器件。更重要的是，本项目的成功将会极大的推进对螺旋电子束深层物理特性的理解，揭示螺旋电子束与材料间相互作用的基本物理规律。

中文关键词： 电子显微学；轨道角动量；螺旋电子束；原子尺度磁成像；纳米材料操控

英文摘要： In this project we will exploit new possibilities opened up by the succesful demonstration of our ability to create electron vortex beams in a transmission electron microscope. Electron vortex beams carry a helical phase and angular momentum around their propagation axis. They form the counterpart of optical vortex beams that were invented almost 20 years ago and have lead to many exciting new applications in optics. In preliminary experiments with electron vortices I have demonstrated (Nature, 467 (2010) 301) their usefulness for magnetic state mapping. This property makes them very desirable for solid state physics and materials science since no other tool exists that can map the local magnetisation inside materials with atomic scale resolution. We aim to develop atomic resolution magnetic state mapping and apply it to gain insight in spintronics devices as well as in topological insulators. We will follow two routes to this goal, one using the combination of electron vortex beams and electron energy loss spectroscopy (EELS) and another making use of the Aharanov Bohm effect in elastic scattering. Preliminary experiments proof that both routes are feasible and a wealth of interesting physics is ready to be explored. We will also explore the potential of electron vortex beams to manipulate nanoparticles and transfer angular momentum from the electron beam to these particles. This would open up the road to assemble and create nanoscale devices and to study the fundamental laws that govern the interaction between vortex beams and particles with different physical properties. I believe this combination of a strong track record, a highly creative idea, access to a state of the art transmission electron microscope makes me an ideal candidate for carrying out this project.

英文关键词： electron miroscopy;orbital angular momentum;electron vortex beams;magnetic state mapping;manipulate nanomaterials