Ultra-thin topological insulator spin-current transistor

超薄拓扑绝缘体自旋电流晶体管

• 批准号: 2881674
• 金额: --
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2881674
• 关键词: Ultra; thin; topological; insulator; spin

Topological insulators are an existing class of band-gap insulators, whilst they do conduct through their edge (or the surface in the case of 3 dimensional materials). These gapless metallic surface states are naturally generated with helically polarized spin texture due to strong spin-orbit coupling with a peculiar energy band structure of materials. Moreover, the states are protected by time-reversal symmetry simply due to prohibition of back scattering and realize almost dissipation-less pure spin currents (no net charge current) at the edge (surface) of materials. Spin-current devices based on the topological insulators save energy because it requires small current that flow at the edge (the surface) not in the bulk to access their surface properties. In this project, we will fabricate a spin-current field effect transistor with an ultra-thin topological insulator Bi2-xSbxTe3 and GeTe (a Weyl semimetal candidate) films grown by molecular beam epitaxy in ultrahigh vacuum, a part of a new multi-deposition system in Leeds. Existence of gapless states in topological insulators (topological Weyl semimetals) are one of peculiar characteristics but we will open a gap in the surface state by employing ultra-thin films where the top and bottom surface states get unstable due to an interference between two. The gapped surface state with a gating technique will provide us a capability of fabricating a spin-current filed effect transistor that can switch on/off the spin-polarized current. We will also keep our eye on other topological insulator materials suitable for this device project. This is a project in an exciting and very active research area which allows us to closely interact and collaborate with other research teams in the University of Leeds including a theoretical group. We are looking for a motivated student with a background in physics, physical chemistry, or material science

拓扑绝缘体是一类现有的带隙绝缘体，同时它们确实通过其边缘（或 3 维材料的表面）进行导电。由于与材料特殊能带结构的强自旋轨道耦合，这些无间隙金属表面态自然产生螺旋极化自旋织构。此外，由于反向散射的禁止，这些态受到时间反转对称性的保护，并在材料边缘（表面）实现几乎无耗散的纯自旋电流（无净电荷电流）。基于拓扑绝缘体的自旋电流器件可以节省能量，因为它需要在边缘（表面）而不是在本体中流动的小电流来访问其表面特性。 在这个项目中，我们将制造具有超薄拓扑绝缘体 Bi2-xSbxTe3 和 GeTe（Weyl 半金属候选）薄膜的自旋电流场效应晶体管，薄膜是在超高真空中通过分子束外延生长的，这是新型多重沉积的一部分利兹的系统。拓扑绝缘体（拓扑外尔半金属）中存在无间隙态是其独特的特征之一，但我们将通过采用超薄膜在表面态中打开一个间隙，其中顶部和底部表面态由于两者之间的干涉而变得不稳定。采用选通技术的带隙表面态将为我们提供制造自旋电流场效应晶体管的能力，该晶体管可以打开/关闭自旋极化电流。我们还将密切关注适合该设备项目的其他拓扑绝缘体材料。 这是一个令人兴奋且非常活跃的研究领域的项目，使我们能够与利兹大学的其他研究团队（包括理论小组）密切互动和合作。我们正在寻找具有物理、物理化学或材料科学背景的积极进取的学生