Spin-resolved electronic structure imaging and microscopy

Understanding the electronic properties of advanced materials is key to enabling and improving a myriad of practical applications. Angle-resolved photoemission spectroscopy is one of the most powerful probes of their low-energy electronic excitations, which ultimately govern the physical properties of solids. As such, it provides key fundamental insights on the novel states and phases found in complex material systems, as well as on their potential for technology. Combining the latest developments in detector technology, laser light sources, and electron scattering for spin polarimetry, we will create a unique and powerful system that not only enables high-resolution and microscopic-focus angle-resolved spectroscopy from a range of challenging materials systems and environments, but also provides the only UK capability for spin-resolved electronic structure imaging. This promises transformative advances in our understanding of the electronic structure of materials, and in particular their spin-dependent properties, laying the framework for applications ranging from solar cells to spintronic and quantum technologies. It will advance a new form of microscopy, where detailed spectral properties provide a unique contrast mechanism for imaging, and will open new routes to study prototype devices in operando, complementing capabilities of key national facilities. It will leverage existing expertise and facilities within the Centre for Designer Quantum Materials in St Andrews, providing critical feedback to enable the targeted design of quantum, spintronic, magnetic, and electronic materials and devices, and will support a wide user base from across the UK, underpinning a broad array of research areas ranging from catalysis to two-dimensional and topological materials.

The impressive recent developments in laser sources, 2D analysers, and spin polarimetry for angle resolved photoemission spectroscopy (ARPES) have created an exciting opportunity for a unique new facility at the time when it is most needed.

There is an increasing realisation of the importance of spin-resolved electronic structures for a wide range of technologies, from energy materials to quantum computing. For example, a new generation of quantum materials, highlighted by the 2016 Nobel Prize in Physics which celebrated the growing importance of 'topological materials', has led to massive worldwide investment in topological quantum computing (see, for example, Microsoft's investments in Station Q at the University of California, Santa Barbara as well as the Center for Quantum Devices at the Niels Bohr Institute and Station Q Delft). Spin-resolved ARPES (SARPES) is the only experimental technique capable of directly measuring the spin-dependent electronic structure which underpins such quantum devices, but the few open SARPES facilities across the world are heavily oversubscribed and there is currently no UK SARPES facility. By combining the latest generation SARPES detectors with advances in focussed ultraviolet laser sources, we will create a new capability that significantly exceeds state-of-the-art, which will attract the best scientists from across the UK and around the world. As a flagship instrument, it will add to the UK's capability in electronic structure and designer quantum materials, an area of existing national excellence. The micro-SARPES facility will complement the world-leading ARPES research at Diamond Light Source (I05 and I09), time- and spatially-resolved ARPES at the UK Central Laser facility (ARTEMIS) and the University of Bristol (nanoESCA), respectively, and combine directly with thin-film growth facilities at St Andrews to create a unique capability for the fabrication and characterisation of designer quantum materials.

By promoting to the wide potential user base and prioritising usage according to scientific merit, we will ensure that the facility delivers high-impact research that will be of general interest across disciplines. We will maximise usage by: disseminating evidence of the high spatial, angular and energy resolution; targeted advertising to potential users and through academic networks; and promoting its excellent scientific output. The knowledge created through the facility will underpin scientific advances across research areas such as: topological materials; correlated electron systems including magnetism and superconductivity; two-dimensional materials and heterostructures; photocathodes; catalysis; and energy materials. The new capabilities will support existing and new research, and researchers, across these fields, and stimulate new collaborations and new networks. The facility will also provide critical skills training for PhD students and early-career researchers, yielding a new generation of highly-skilled personnel to seed progress in research and innovation. Ultimately our vision is for the facility to act as a visible hub for UK research on the electronic and spintronic properties of advanced materials, and to facilitate the development of new technologies for manipulating and utilising spin in electronic devices.

The unique facility enabling the integrated measurement and growth of designer quantum materials and prototype quantum devices will also be a draw for industrial collaboration. We will promote this through industrial engagement via knowledge transfer networks, and will make the facility open (with access charges) to industrial users, offering full technical support.