Micrometer-scale time-resolved ARPES on exfoliated quantum materials and their heterostructures

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This proposal is for the purchase of equipment required to increase the spatial resolution of our current state-of-the-art time- and angle-resolved photoemission spectroscopy (TR-ARPES) system to less than 10 micrometers, to build the first system of this kind in the whole world. This new capability to perform time-resolved micro-ARPES (TR-ARPES) measurements at the micron-scale will result in the first system of this kind in the whole world, and will allow for ground-breaking studies on two-dimensional (2D) material heterostructures hosting exotic quantum phenomena at the very forefront of condensed matter physics research. In particular, this will allow us to study the ultrafast relaxation dynamics of the unconventional, strongly-correlated superconducting phase in magic angle' twisted bilayer graphene devices, as well as a plethora of phases (charge density wave, quantum spin Hall insulating) hosted in mono- and few-layer transition metal dichalcogenides (TMDCs), such as NbSe2 and WTe2. **********UBC is uniquely positioned to lead this new research effort, by combining expertise in ARPES (Damascelli), ultrafast optics (Jones), and 2D material fabrication techniques (Folk) all within the same building at the Quantum Matter Institute (QMI). The QMI at UBC is currently home to a state-of-the-art TR-ARPES system developed by Damascelli and Jones with funding representing a first for Canadian science research from the Gordon and Betty Moore Foundation. This world-class ultrafast system is already capable of delivering the necessary high-energy photons (8-40 eV) at high repetition rates to probe the quantum phenomena in 2D material heterostructures, and is only lacking the equipment required to focus the laser spot size to the typical microscopic sample dimensions.