SPIN ELECTRONICS: Spintronics in Y-junction carbon nanotubes

自旋电子学：Y 结碳纳米管中的自旋电子学

• 批准号: 0223943
• 负责人: Jimmy Xu
• 金额: $ 30万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0223943&HistoricalAwards=false
• 关键词: SPIN; ELECTRONICS; Spintronics; junction; carbon

This proposal was received in response to the Spin Electronics for the 21st Century Initiative, Program Solicitation NSF 02-036. The proposal focuses on spin dependent transport and spintronics functionality in a unique nanostructured system - Y-junction Carbon Nanotubes.The Y-junction nanotubes, first fabricated by one of the PIs (JMX)-combine the attractive properties of carbon nanotubes (effectively 1D electronic transport with long ballistic mean free paths and exceptionally high current densities)with a three-terminal geometry and a built-in heterojunction barrier at the Y-branching point. Spin transport in ordinary, straight ferromagnetically contacted multi-walled carbon nanotubes, first studied by another of the PIs, has yielded excellent spin-polarized injection efficiencies and long spin-scattering lengths on the order of 0.25 um, making ferromagnet-nanotube hybrids a promising spintronics platform. The spin transport in a Y-junction with the built-in heterobarrier is already interesting and unexplored. But what makes the proposed devices unique is the possibility applying both ferromagnetic and normal metal contacts to the three terminals of the Y-junction, as well as using different ferromagnetic materials (with separately switchable magnetizations)for contacts to the same device. This unprecedented flexibility will enable us, for example, to clearly distinguish spin-mediated injection and extraction of currents from ordinary injection, tune the transmission of spin up and spin down electrons by means of a control voltage on the third terminal, witch the spin-coherent current from one Y-junction arm to another by switching the magnetization with an external field, and more generally produce a true three-terminal spintronic transistor. However great the potential of this new nanostructured system may be, a great amount of challenging work, from fabrication of the Y-junction nanotubes to fabrication of nano-scale contacts to cryogenic measurements of the contacted Y-junctions in the presence of magnetic fields externally modulated, will have to done first to prove the concepts. This NSF project is launched for these proof-of-concept explorations, and for paving the pathway to this new and exciting field of opportunities.

该提案是为了响应 21 世纪自旋电子学计划 NSF 02-036 计划征集而收到的。 该提案的重点是独特的纳米结构系统（Y 结碳纳米管）中的自旋相关输运和自旋电子学功能。Y 结纳米管首先由其中一位 PI (JMX) 制造，结合了碳纳米管的有吸引力的特性（有效地一维电子具有长弹道平均自由程和极高电流密度的传输），具有三端几何结构和 Y 分支点内置异质结势垒。另一位 PI 首次研究了普通直铁磁接触多壁碳纳米管中的自旋输运，它产生了出色的自旋极化注入效率和 0.25 um 量级的长自旋散射长度，使铁磁体-纳米管杂化物成为一种有前途的材料自旋电子学平台。具有内置异质势垒的 Y 结中的自旋输运已经很有趣且尚未探索。但所提出的设备的独特之处在于可以将铁磁和普通金属触点应用于 Y 结的三个端子，以及使用不同的铁磁材料（具有可单独切换的磁化强度）作为与同一设备的触点。 例如，这种前所未有的灵活性将使我们能够清楚地区分自旋介导的电流注入和电流提取与普通注入，通过第三端子上的控制电压来调整自旋向上和自旋向下电子的传输，从而使自旋通过用外部场切换磁化强度，相干电流从一个 Y 结臂转移到另一个 Y 结臂，更一般地产生一个真正的三端自旋电子晶体管。无论这种新型纳米结构系统的潜力有多大，从 Y 结纳米管的制造到纳米级接触的制造，再到在外部磁场存在的情况下对接触的 Y 结进行低温测量，都存在大量具有挑战性的工作调制，必须首先证明概念。 这个 NSF 项目是为了这些概念验证探索而启动的，并为这个新的、令人兴奋的机会领域铺平道路。