Topological Insulators: A study of bulk crystalline and Nanomaterials

拓扑绝缘体：块状晶体和纳米材料的研究

• 批准号: EP/L014963/1
• 负责人: Geetha Balakrishnan
• 金额: $ 61.63万
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FL014963%2F1
• 关键词: Topological; Insulators; study; bulk; crystalline

Topological Insulators (TIs) are a class of quantum materials that exhibit topological surface states. These materials are usually small band gap semiconductors where the bulk of the material is insulating, but they exhibit special surface states that are conducting and topologically protected. The materials are usually made of heavy atoms that give rise to strong spin-orbit coupling and this leads to the formation of surface states that are not destroyed by scattering or impurities. TIs are proving to be ideal materials for study in condensed matter physics, as the physics of these materials is novel and they offer huge scope for developing new theories and for the discovery of new materials. Although the TIs have gapless edge or surface states that are protected and are in theory supposed to have an insulating gap in the bulk, most of the 3D TIs discovered to date are still fairly conducting in the bulk. Materials design and processing have emerged as being key to the investigation and the discovery of new TIs. The challenge for materials physicists is to create TI materials that are true insulators in the bulk, in order to facilitate the study of their exotic surface states.In this proposal, we describe the methodology to be adopted to obtain high quality materials, for the different experiments proposed. We propose to synthesize a range of materials, some of which are already known to be Topological Insulators and other new materials such as the Topological Crystalline Insulators (TCIs) and those with emerging topological behaviour. The project will investigate both bulk crystalline materials and nanomaterials (in the form of nanoplatelets and nanorods). The study of the emergence of superconductivity in the 3D TIs and TCIs will be undertaken. The existence of a full pairing gap in the bulk in the superconducting Topological Insulators, together with the gapless surface states in these materials, makes them extremely interesting.The physics of these materials will be investigated through detailed studies of the bulk properties of the crystals (including resistivity and Hall effect, magnetisation, heat capacity) in particular, to understand the influence that the bulk electronic and magnetic properties have on their topological behaviour. X-ray/electron diffraction and electron microscopy techniques will be used for the investigation of the structural properties of both the crystals and nanomaterials. Investigations of the surfaces of the crystalline and nanomaterials by XPS and ARPES will be carried out with our collaborators. Neutron scattering and muon spectroscopy techniques will also be employed. Valuable theoretical input from the Project Partner will be used in conjunction with the results from the experimental investigations, to inform the decisions for the design and fabrication of new materials exhibiting TI behaviour.A wide network of experts, including both therorists and experimentalists, as collaborators will contribute to successfully deliver the work described this project.

拓扑绝缘体（TI）是一类表现出拓扑表面态的量子材料。这些材料通常是小带隙半导体，其中大部分材料是绝缘的，但它们表现出特殊的表面状态，即导电和拓扑保护。这些材料通常由重原子组成，重原子产生强烈的自旋轨道耦合，这导致形成不被散射或杂质破坏的表面态。TI被证明是研究凝聚态物理的理想材料，因为这些材料的物理学是新颖的，它们为发展新理论和发现新材料提供了巨大的空间。虽然TI具有受保护的无间隙边缘或表面状态，并且理论上应该在体中具有绝缘间隙，但迄今为止发现的大多数3D TI在体中仍然相当导电。材料设计和加工已成为研究和发现新TI的关键。材料物理学家面临的挑战是创造出真正的大块绝缘体TI材料，以促进对其奇异表面态的研究。在本提案中，我们描述了针对不同实验获得高质量材料所采用的方法。提出。我们建议合成一系列材料，其中一些已经被称为拓扑绝缘体和其他新材料，如拓扑晶体绝缘体（TCI）和那些新兴的拓扑行为。该项目将研究块状晶体材料和纳米材料（以纳米片和纳米棒的形式）。将对3D TI和TCIs中超导性的出现进行研究。在超导拓扑绝缘体中，体材料中存在完整的对能隙，再加上这些材料中的无能隙表面态，使得它们非常有趣。这些材料的物理将通过对晶体体性质的详细研究来研究（包括电阻率和霍尔效应、磁化强度、热容），了解体电子和磁性对其拓扑行为的影响。X射线/电子衍射和电子显微镜技术将用于晶体和纳米材料的结构特性的调查。通过XPS和ARPES对晶体和纳米材料表面的研究将与我们的合作者一起进行。中子散射和μ子光谱技术也将被采用。来自项目合作伙伴的有价值的理论输入将与实验研究的结果结合使用，以告知展示TI行为的新材料的设计和制造的决策。广泛的专家网络，包括理论家和实验家，作为合作者将有助于成功交付本项目所描述的工作。

项目成果

Probing the interplay between surface and bulk states in the topological Kondo insulator SmB$_6$ through conductance fluctuation spectroscopy

通过电导涨落光谱探测拓扑近藤绝缘体 SmB$_6$ 中表面态和体态之间的相互作用

• DOI: 10.48550/arxiv.1705.10040
• 发表时间: 2017
• 作者: Biswas S

Fermi surface in the absence of a Fermi liquid in the Kondo insulator SmB6

• DOI: 10.1038/nphys4295
• 发表时间: 2018-02-01
• 期刊: NATURE PHYSICS
• 影响因子: 19.6
• 作者: Hartstein, M.;Toews, W. H.;Sebastian, Suchitra E.
• 通讯作者: Sebastian, Suchitra E.

Observation of surface states on heavily indium doped SnTe(111), a superconducting topological crystalline insulator

超导拓扑晶体绝缘体重掺铟 SnTe(111) 表面态的观察

• DOI: 10.48550/arxiv.1508.03848
• 发表时间: 2015
• 作者: Polley C

Exceptional surface and bulk electronic structures in a topological insulator, Bi2Se3.

• DOI: 10.1038/srep17351
• 发表时间: 2015-12-08
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Biswas D;Thakur S;Balakrishnan G;Maiti K
• 通讯作者: Maiti K

Signatures of the Kondo effect in VSe2

VSe2 中近藤效应的特征

• DOI: 10.48550/arxiv.1709.00594
• 发表时间: 2017
• 作者: Barua S