Grant: Research Tools and Instruments

This proposal is for the development of a custom-made system for the in-vacuum fabrication of twisted 2-dimensional (2D) heterostructures made of micro-exfoliated high-Tc superconductors (HTSC). This system will allow us to realize the ground-breaking concept developed by the Quantum Matter Institute (QMI) team led by Marcel Franz and Andrea Damascelli, who have predicted that topological superconductivity at high temperature can be achieved by stacking two monolayers of HTSCs with a twist angle of 45°. The successful micro-fabrication of a high-Tc topological superconductor holds great promise towards the realization of Majorana particles in solid-state devices, and ultimately pave the way to robust topological quantum computation.     To establish topological superconductivity in atomically-thin materials, the technique of angle-resolved photoemission spectroscopy (ARPES) - with its exquisite surface sensitivity - is essential. The challenge in manufacturing and measuring twisted devices lies in ensuring the pristine quality and contamination-free nature of both top surfaces and twisted interfaces. This requires fabrication to take place in an ultra-high vacuum (UHV) environment, and then a direct in vacuum connection to the ARPES spectrometer to avoid exposure to atmosphere. The proposed equipment will employ exclusively in-UHV tools to exfoliate monolayers of HTSC samples onto a substrate and then onto existing monolayers; this instrument will offer positioning of samples accurate at the micron level, with sub-degree angular precision, and optical access through a microscope to achieve the extreme control this procedure requires.     UBC is uniquely positioned to spearhead this ground-breaking research initiative by harnessing the collective expertise in ARPES and 2D-material fabrication techniques (Damascelli), as well as in-house theoretical leadership (Franz) - all conveniently situated within the QMI building on the UBC Vancouver Campus. The instrument will be integrated into the existing ARPES preparation chamber in Damascelli's UBC-Moore Centre for Ultrafast Quantum Matter. This world-class ARPES infrastructure already possesses the necessary capabilities for measuring twisted devices, owing to its low-temperature sample stage, cutting-edge energy resolution, and recently developed micro-ARPES capabilities for micro-exfoliated monolayers, enabling measurements on devices as small as a few micrometers. The only missing tool is the equipment required to produce pristine and ultra-clean twisted HTSC heterostructures within the UHV environment.