An integrated materials nanofabrication workstation to stack membranes for the Quantum Materials and Device Foundry

该提案是为了紧急购买一个集成的纳米加工工作站，用于堆叠膜，该工作站基于一个精密的惰性气氛手套箱，带有计算机控制的显微镜，直接连接到UBC量子材料和器件铸造厂现有的分子束外延（MBE）系统，该系统是量子材料研究所（QMI）的一部分。在工作站中，我们将采用独特的“剥离和堆叠”技术组合，首次从MBE生长的薄膜中创建独立的原子级薄的氧化物和硫族化合物堆栈。剥离技术几乎总是应用于石墨烯或硫族化合物材料，这些材料的晶体可以在它们的弱键“范德壁”（vdW）层之间优先被扯开；但是到目前为止，原子级的氧化物和硫族化合物层的堆叠还没有成功的报道。关键是，针对硫系材料开发的标准剥离技术不适用于氧化物，因为绝大多数技术上有趣的氧化物（铁电、铁或反铁磁、多铁磁）都是强三维键合的，没有弱键合的vdW层。相反，最近在2019年开发了一种新的钙钛矿氧化物“升空”技术，使用一种水溶性牺牲缓冲层，一旦溶解，就可以让上面的氧化物自由漂浮。令人惊讶的是，所得到的层保持了它们的铁性质，甚至只有几个原子层的厚度。这为创建和堆叠氧化物和硫族化物层提供了基础，开辟了一个以前从未研究过的材料组合的巨大游乐场，这些材料可能具有新的和完全意想不到的电子特性。为了避免暴露在空气中的污染，工作站设计需要一个真空负载锁，允许从我们的MBEs超清洁转移到手套箱中，在手套箱中进行准备和堆叠。工作站的主要目标是通过将材料结合成独立的原子层堆栈，在我们的mbe中生长成薄膜，为设计和构建新型量子材料创造新的尖端能力。我们将专注于材料的组合，这些材料可以提供一个与QMI大挑战（https://qmi.ubc.ca/grand-challenges）中的相关研究重点相一致的新兴特性平台。更广泛地说，新的量子材料构成了加拿大未来量子技术路线图的关键部分，该提案为具有战略重要性的高素质人才（HQP）提供了广泛有用的培训机会。该工作站的创新能力非常适合在UBC QMI内的凝聚态物理和纳米科学社区以及UBC以外的外部加拿大机构中产生新的合作。

This proposal is for the urgent purchase of an integrated nanofabrication workstation for stacking membranes, based on a precision inert-atmosphere glovebox with computer-controlled microscope interfaced directly to the existing molecular-beam epitaxy (MBE) systems in the Quantum Materials and Devices Foundry, part of the Quantum Materials Institute (QMI) at UBC. In the workstation, we will apply a unique combination of "exfoliation and stacking" techniques to create, for the first time, freestanding atomically-thin stacks of oxides and chalcogenides from thin films grown by MBE. Exfoliation techniques are nearly always applied to graphene or chalcogenide materials whose crystals can be preferentially pulled apart between their weakly-bonded "van der Walls" (vdW) layers; but so far, stacking of atomically-thin layers of oxides and chalcogenides has never been successfully reported. Critically, standard exfoliation techniques developed for chalcogenide materials do not work for oxides because the vast majority of technologically interesting oxides (ferroelectric, ferro- or antiferromagnetic, multiferroic) are strongly 3-dimensionally bonded with no weakly-bonded vdW layers. Instead, a new "lift-off" technique for perovskite oxides has been recently developed in 2019 using a water-soluble sacrificial buffer layer that, once dissolved, allows the overlying oxide to float off freely. Surprisingly, the resulting layers keep their ferroic properties even down to thicknesses of a few atomic layers. This provides the groundwork for creating and stacking together oxide and chalcogenide layers, opening up a huge playground of materials' combinations never before studied that may possess new and completely unexpected electronic properties. To avoid contamination from air exposure, the workstation design requires a vacuum loadlock allowing ultra-clean transfer from our MBEs into the glovebox where the preparation and stacking will be done. The primary goal of the workstation is to create new cutting-edge capabilities for designing and constructing novel quantum materials by combining materials, grown as thin films in our MBEs, into freestanding atomic-layer stacks. We will focus on combinations of materials that can provide a platform for emergent properties aligned with relevant research thrusts within the QMI Grand Challenges (https://qmi.ubc.ca/grand-challenges). More broadly, new quantum materials form a key part of Canada's roadmap for future quantum technologies and this proposal offers a broad range of useful training opportunities for highly qualified personnel (HQP) of strategic importance. The innovative capabilities of the proposed workstation is perfectly placed to generate new collaborations in condensed matter physics and nanoscience communities within the QMI at UBC, and external Canadian institutions beyond UBC.