Spin resolution at SKIF and SLS

Coherent synchrotron radiation takes an important place in modern condensed matter research and has provided a significant boost in the study of structural and electronic properties of novel materials. High brilliance and tuneable UV and soft X-ray radiation as generated by modern synchrotron facilities has made the detailed electronic structure research possible that has proven essential in the study of for example unconventional superconductors and topological quantum materials. The technique of angle-resolved photoemission spectroscopy (ARPES) provides direct access to the band structure of crystals, nanostructures, and 2D materials like graphene, and is the only measurement technique that does so without relying on extensive modelling.

Combined with spin resolution (SARPES), the possibilities are even further expanded. Most straightforward examples are the measurement the spin texture of magnetic materials and materials where spin-orbit interaction lifts the spin degeneracy of states, aimed at spin-orbitronics applications. However, especially in combination with tuneable synchrotron radiation, more advanced experiments become feasible, such as separating spin-singlet and -triplet arrangements, performing magnetic circular dichroism in fluctuating systems above the tradition temperature, measuring hidden order parameters, and even accessing the time scale of the photoemission process itself. Such measurements require a combination of dedicated advanced experimental facilities, high quality samples, and a large amount of experience.

The COmplete PHotoEmission Endstation (COPHEE) at the Swiss Light Source has for two decades been in the forefront on competitive SARPES research and we have gained a significant amount of experience from this. On the other hand, the team in Novosibirsk has experience in sample growth and novel spin detection techniques, and most importantly, will be involved in the construction and running of state-of-the-art new synchrotron radiation facility called SKIF. The aim of this project is to disseminate knowledge and experience related to SARPES experiments especially among young researchers both in Russia and Switzerland. This will secure that this know-how, which is now in the hands of only relatively few people, will be carried on to future generation of scientists and that the technique will be able to reach its full potential. Furthermore, the scientific exchange stimulated by this project will be used to optimise the design of novel SARPES instrumentation and provide ideas on how to optimally use the characteristics of novel synchrotron radiation. This will benefit both the new beamlines to be built at the SKIF synchrotron in Novosibirsk and pending upgrades at the Swiss Light Source.

The budget will be used to partially finance a SARPES workshop in Novosibirsk for young scientists with lectures given by experts in the field, and further to allow for travel between Russia and Switzerland to study and exchange ideas on experimental equipment and to gain experience with state-of-the-art SARPES experiments. The details of the workshop and travel organisation will depend on any restrictions following the Covid-19 crisis.

Participants:

Ecole Polytechnique Fédérale de Lausanne:

Rzhanov Institute of Semiconductor Physics SB RAS: