Grant: Research Tools and Instruments

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.