PhD Studentship: Interfacial Spin-orbit Coupling Based Superconducting Spintronics

Primary Supervisor: Dr Niladri Banerjee (n.banerjee@imperial.ac.uk)

Co-supervisor: Prof. Lesley Cohen

Applications are invited for a research studentship in the field superconductivity and spin-based electronics (spintronics), leading to the award of a PhD degree. The post is supported by a bursary and fees (at the UK student rate) provided by the EPSRC. The candidates should fulfil the eligibility criteria for the award.

Summary of the project

Spin-based electronics (spintronics) which uses the electron spin for reading, writing and processing information plays a crucial role in modern computing and data storage technologies. However, spintronic devices still rely on dissipative charge currents as the source of spin currents and suffer from large heat dissipation. This problem could be potentially addressed using superconductors.

However, conventional superconductivity does not carry a net spin since it is formed of electron pairs with anti-parallel spins - the singlet Cooper pair. In the last decade several experiments1 confirmed the existence of an exotic spin-triplet superconductivity in superconductor-ferromagnet (S/F) thin film hybrids which is formed of equal spin-paired electrons (triplet Cooper pairs) and carries a net spin. However, generating this triplet superconductivity usually requires S/F hybrid structures with complex magnetic textures.

Recently, we demonstrated that S/F hybrids with interfacial spin-orbit coupling and without complex magnetic textures can be used to generate triplets2. In addition to strikingly simplifying the thin film structures, presence of spin-orbit coupling (SOC) in S/F structures raises intriguing new possibilities such as magnetisation reorientation purely driven by superconductivity or magnetically tunable superconducting transistors3.

This PhD project will explore the possibility to fabricate these SOC-based functional devices. For example, a key goal in the project will be to explore the fabrication of SOC-based spin triplet Josephson junctions and study the transmission of triplet supercurrents through materials with high SOC. These results will open up new paradigms in direct electrical control of the spin polarization of supercurrents mediated by SOC.

The student will learn and use thin film deposition and develop expertise in nano fabrication using standard optical and/or electron beam lithography and ion milling. The project will also involve low-temperature measurement of electronic and magnetic properties of thin films and devices.

You will be an enthusiastic and self-motivated person who meets the academic requirements for enrolment for the PhD degree at Imperial College London. Good team-working, observational and communication skills are essential.

Please complete an electronic application form at Imperial College London in order for their qualifications to be addressed by College Registry

References:

1. J. Linder and J. W. A. Robinson, Nature Physics, 11, 307 – 315 (2015)
2. N. Banerjee, et al., Phys. Rev. B., 97, 184521, (2018)
3. M. Amundsen et al., arXiv:2210.03549, (2022)

To find out more about research at Imperial College London in this area, go to:

https://www.imperial.ac.uk/experimental-solid-state/postgraduate/

For information on how to apply, go to:

https://www.imperial.ac.uk/study/apply/postgraduate-doctoral/

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