In situ study of strain- and field-induced phases of quantum matter at the CLS-QMSC Beamline

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This proposal is for the development of a multi-purpose cryo-manipulator to be used at the Quantum Materials Spectroscopy Center (QMSC) beamline at the Canadian Light Source (CLS). This will greatly enrich the capabilities of our state-of-the-art spin- and angle-resolved photoemission spectroscopy (Spin+ARPES) users' facility by introducing multi-purpose electrical contacts onto the sample stage that will enable driving the materials into - and unveiling - novel phases of quantum matter. This technical upgrade is meant to allow Spin+ARPES measurements that probe the electronic structure of solids upon tuning of an unprecedented range of control parameters that are commonly hard or previously impossible to achieve in ARPES spectrometers. This equipment will allow users to: (i) drive currents and apply a bias to the sample; (ii) generate controlled magnetic fields to magnetize the samples in situ; and (iii) apply precise and measurable mechanical strains to the samples. At QMSC we use Spin+ARPES to answer some of the most outstanding fundamental questions of solid state physics and quantum matter, with particular focus on the emergence of exotic phenomena such as high temperature superconductivity, coherent phases induced by electron correlations, and topological phases ranging from topological insulating behavior to topological superconductivity. The microscopic understanding, the design and engineering of better quantum materials, and their ultimate exploitation in functional devices all rely on our ability to induce and elicit these exotic phenomena in a deliberate and controlled manner through external stimuli. To this end, materials can be driven into new phases by external electrical bias, or by structural modification through mechanical strain, or by the application of magnetic fields. Achieving precise tuning of these "control knobs" in an ARPES experiment is a major technical challenge, since this must be done in an ultra-high vacuum environment at cryogenic temperatures. We propose to overcome these difficulties and create a universal solution by reengineering a commercial 6-axis cryo-manipulator with electrical contacts - purchased with this RTI - to host samples mounted on custom-made sample-holders. Controlling the voltages on the electrical contacts will make it possible to generate magnetic fields in-situ, run current through the samples, and to apply an exquisitely precise mechanical strain. For the latter, a commercial Razorbill strain-cell, that can deliver highly accurate and repeatable strain on the samples, is purchased and adapted to be hosted on our cryogenic sample holders. This RTI will support a long-lasting research program in experimental condensed matter physics focused on studies of superconductivity and other exotic quantum phenomena, but also provide QMSC@CLS, as well as our national and international users' community, with a unique world-competitive experience.