Quantum Materials by Twistronics

Twistronics 的量子材料

基本信息

批准号：
EP/V007033/1
负责人：
Roman Gorbachev
金额：
$ 164.36万
依托单位：
University of Manchester
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2021
资助国家：
英国
起止时间：
2021 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FV007033%2F1
关键词：
Quantum Materials Twistronics

项目摘要

Two-dimensional materials (2DM), derived from bulk layered crystals with covalent intra-layer bonding and weak van der Waals (vdW) interlayer coupling, offer a versatile playground for creating quantum materials with properties tailored for particular applications. This is achieved by combining different atomically thin 2DM crystals into heterostructures layer-by-layer in a chosen sequence. Unlike conventional crystal growth, this technique is not limited by lattice matching or interface chemistry, hence, it enables us to build heterostructures from several dozens of readily available vdW crystals with diverse physical properties (electronic, optical or magnetic). This platform offers broadly acknowledged potential for the realisation of nano-devices and designer meta-materials with new properties and functionalities determined by the coupling of adjacent layers, including interlayer band hybridisation and strong proximity effects.A new degree of freedom for controlling the properties of vdW heterostructures is the mutual crystal rotation - twist - of the constituent 2D crystals. Together with the lattice mismatch of the adjacent 2D crystals it gives rise to the moiré superlattice (mSL): a periodic variation of the local atomic registry, with the period controlled by the twist angle. Even a small twist can lead to remarkable changes in the properties of heterostructures - for instance, in homobilayers of 2DM it leads to strong spectrum reconstruction and formation of electron and hole minibands. So far, the breakthrough studies of moiré superlattices have been focused on graphene heterostructures with hexagonal boron nitride and on twisted graphene bilayers. Recently, initial exploration of twisted layers of transition metal dichalcogenides have begun, featuring four letters in a single issue of Nature in March 2019 (in one of those the members of this consortium have reported moire minibands for excitons). Not surprisingly, these recent developments have fuelled a world-wide race to develop this new field of materials science and solid state physics, branded as 'twistronics'. This project will pioneer the new scientific area of twistronics in novel types of 2DM heterostructures, mapping out the limits to which one can control their properties through the interlayer proximity and moiré superlattice effects. Using this approach, we aim to engineer flat electronic bands in semiconducting 2DM heterostructures, promoting quantum many-body effects, which we will explore through quantum transport and optical studies. Furthermore, we will realise the world-first twisted bilayers of new emerging 2DMs that exhibit strongly correlated states in their natural form ((anti)ferromagnetic, charge-density waves, or superconductivity) and explore novel physics in those system with an outlook for practical applications. In all material combinations, we will look into two distinct cases of (1) intermediate twist angles, where lattices are expected to behave as rigid solids, producing smooth variation in interlayer registry and (2) small twist angles where we have recently found that twisted 2D materials reconstruct to form extended commensurate domains separated by stacking faults. To achieve the ambitious and game-changing goals of this proposal, the consortium will employ a recently commissioned world-first nanofabrication facility, which allows assembly of van der Waals heterostructures in ultra-high vacuum. This unique instrument will provide the game-changing quality materials necessary for this project. Funding of this proposal will allow us to fully employ the potential of this new instrument and deliver ground-breaking new research and disruptive technologies.

二维材料（2DM），这些材料来自具有共价层内键和弱范德华（VDW）中间层偶联的散装分层晶体，提供了一个多功能操场，用于创建具有适用于特定应用的属性的量子材料。这是通过将不同的原子薄2DM晶体组合到选择序列中逐层的异质结构中来实现的。与常规的晶体生长不同，该技术不受晶格匹配或界面化学的限制，因此，它使我们能够从具有多种物理特性（电子，光学或磁性）的数十个易于使用的VDW晶体中构建异质结构。该平台为实现纳米设备和设计器元物质的实现提供了广泛的承认潜力，其新属性和功能是通过相邻层的耦合确定的，包括层间层带杂交和较强的接近性效应。连同相邻2D晶体的晶格不匹配，它产生了Moiré超晶格（MSL）：局部原子注册表的周期性变化，并由扭角控制。即使是一个小的扭曲也会导致异质结构的性质发生显着变化 - 例如，在2DM的同型物体中，它会导致频谱重建和形成电子和孔迷你吧。到目前为止，对Moiré超级晶格的突破研究一直集中在具有六角形硝化硼和扭曲的石墨烯双层的石墨烯异质结构上。 Recently, initial exploration of twisted layers of transition metal dichalcogenides have begun, featuring four letters in a single issue of Nature in March 2019 (in one of those members of this consortium have reported moire minibands Not surprisingly, these recent developments have fuelled a world-wide race to develop this new field of materials science and solid state physics, branded as 'twistonics'. This project will pioneer the new scientific area of twistronics in novel types of 2DM异质结构，绘制通过使用这种方法来控制其特性的限制，我们旨在使用这种方法来设计扁平的电子带，以半导体的方式进行2DM异质效果2DMS以自然形式强烈相关的状态（（（反）铁磁，电荷密度波或超导性），并探索具有实用应用前景的那些系统中的新型物理学。在所有材料组合中，我们将研究两种不同的情况，即（1）中间扭曲角，预计晶格将表现为刚性固体，从而产生层间注册表中的平稳变化，以及（2）小扭曲角度，我们最近发现，扭曲的2D材料重建以形成扩展的伸展域，由堆叠断层分离。为了实现该提案的雄心勃勃和改变游戏规则的目标，该财团将采用最近受过委托的世界优先制作设施，该设施允许在超高真空中组装范德华异质结构。这种独特的仪器将为本项目提供改变游戏规则的优质材料。该提案的资金将使我们能够充分利用这种新工具的潜力，并提供开创性的新研究和破坏性技术。