EAPSI: Fundamental experimental materials physics for next generation electronics devices

EAPSI：下一代电子设备的基础实验材料物理

• 批准号: 1414628
• 负责人: John Hellerstedt
• 金额: $ 0.51万
• 依托单位: Hellerstedt John
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1414628&HistoricalAwards=false
• 关键词: EAPSI; Fundamental; experimental; materials; physics

Moore's "law", describing the fantastic increase in performance of transistors, the fundamental building block of computers, is approaching fundamental quantum limits of scalability and performance. These hard limits of smallest size and fastest speed coincide with the explosion of demand for electronics, from phones to the data centers underpinning the internet, and the environmental consequences of generating the electricity to power this infrastructure. One possible solution is to develop an alternative transistor based on a completely different physics: manipulation of the spin state of an electron in place of conventional voltage modulation. Over the past decade, an exciting new field of condensed matter physics, topological insulators, has theoretically postulated and experimentally realized a class of materials possessing a non-trivial relationship between electron spin and momentum. This crucial coupling between the two properties could be the link between the existing paradigm of electronics and future realizations of faster, vastly more energy efficient devices. However the current materials in which these properties are realized remain far from robust in the environmental conditions required to be more than a scientific curiosity. To better understand these existing materials limitations, this project takes advantage of an experimental technique available at Professor Yukio Hasegawa's laboratory at the Institute of Solid State Physics, University of Tokyo, called spin-polarized scanning tunneling microscopy (SP-STM), capable of measuring the spin states of electrons with atomic scale spatial resolution.SP-STM is a particularly well-suited experimental technique within this context; being surface sensitive and atomically resolved allows for the direct observation of how the theoretically predicted topological protection manifests itself in scattering at defect sites. Bismuth selenide, the most promising topological insulator to date, has a crystal structure and mechanical properties making surface preparation of samples for STM relatively facile. Measuring the out of plane spin polarization of electrons at scattering sites will clarify the existing theoretical framework used to understand topological insulators, and inform how to utilize the surface states in spin electronic heterostructures. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.

摩尔定律描述了晶体管性能的惊人增长，晶体管是计算机的基本组成部分，它正在接近可扩展性和性能的基本量子极限。这些最小尺寸和最快速度的硬性限制与电子产品需求的爆炸性增长相吻合，从电话到支撑互联网的数据中心，以及为这些基础设施发电的环境后果。一个可能的解决方案是开发一种基于完全不同物理学的替代晶体管：操纵电子的自旋状态来代替传统的电压调制。在过去的十年中，凝聚态物理学的一个令人兴奋的新领域，拓扑绝缘体，已经在理论上假设和实验上实现了一类具有电子自旋和动量之间的非平凡关系的材料。这两种特性之间的关键耦合可能是现有电子学范式与未来实现更快，更节能设备之间的联系。然而，实现这些特性的当前材料在所需的环境条件下仍然远远不够坚固，而不仅仅是科学好奇心。 为了更好地理解这些现有材料的局限性，本项目利用了东京大学固体物理研究所长谷川幸雄教授实验室现有的一种实验技术，称为自旋极化扫描隧道显微镜（SP-STM），能够以原子尺度的空间分辨率测量电子的自旋状态。表面敏感和原子分辨允许直接观察理论上预测的拓扑保护如何在缺陷位置处的散射中表现出来。 硒化铋是迄今为止最有前途的拓扑绝缘体，具有晶体结构和机械性能，使得STM样品的表面制备相对容易。 测量电子在散射位点的面外自旋极化将澄清用于理解拓扑绝缘体的现有理论框架，并告知如何利用自旋电子异质结构中的表面态。 这个NSF EAPSI奖是与日本科学促进协会合作资助的。