PhD Projects
Project 1: Harnessing topological nano-whirls to enable brain-like computing
Supervisor: Hariom Jani
Motivation: Today's computing ecosystem uses 10% of global electricity and contributes 2% of emissions (at par with aviation!). With the rise of AI, autonomous devices and big data, this energy demand will increase sharply, putting strain on global resources. Heart of the problem is that charge-based silicon platforms are volatile, inefficient and serial. This has resulted in a quest for novel quantum materials hosting rich emergent physical properties that can be harnessed to yield high-speed and energy-efficient functionalities.
Topologically-rich antiferromagnets (AFMs), consisting of vortex-like whirling spin textures, are especially promising in this regard, as they host a robust non-volatile magnetic order. It has been theoretically predicted that such nano-whirls can move at incredible speeds of kilometres/second and host rich dynamics up to terahertz frequencies, i.e. 100-1000 times faster than conventional silicon devices. Such magnetic ‘nano-whirls’ could be used to power reservoir computing or logic-in-memory, enabling next-gen AI hardware.
We have pioneered the discovery and control of AFM solitons at room temperature, thus, experimentally opening the field of real-space topological antiferromagnetism. Our breakthroughs have been published in , , , , etc.
Potential project scope: The goal of these DPhil projects is to push this young field toward the ultra-fast dynamical frontiers and thus open doors to its practical utilisation. Students will learn to use cutting-edge spectro-microscopy and dynamical imaging techniques to explore fast AFM dynamics. They will pioneer a versatile toolbox – involving quantum materials design, spintronic control, combined with electrical and optical excitation – to enable targeted spatio-temporal control of AFM nano-whirls. These fundamental breakthroughs are urgently needed to enable transformative next-generation applications, such as soliton race-tracks, terahertz nano-oscillators, AFM magnon nano-emitters, and terahertz reservoir computing for next-gen AI.
We are looking for passionate physics students with:
- a strong academic track record and good exposure to hands-on research
- experience in coding or simulations (e.g. using Python, MATLAB etc.)
- a keen interest in both experimental research and computational modelling
Scientific Techniques: Successful candidates will develop research expertise in both fundamental and applied research. Depending on the candidate's interests, the project may involve developing one or more of the following techniques in combination with computational modelling.
Quantum materials design: Growth of high-quality crystalline thin films and free-standing nano-membranes using integrated pulsed laser deposition and UHV sputtering at advanced growth suites in Oxford Physics, as well as at the Albert Fert Laboratory - CNRS/Thales (Paris) and National University of Singapore (Singapore).
Device fab and characterisation: Nanofabrication of prototype devices will be done using e-beam/optical lithography, laser writing and focused ion beam milling in Oxford’s Class 100 and 1000 cleanrooms. Structure/surface characterisation will be done using in-house high-resolution diffraction, reflectometry and scanning probe microscopy. Physical properties measurement system and custom-built equipment will be used to study electrical properties.
Advanced Microscopy: Imaging of nanoscale multi-functional domains, which form the fundamental unit of information storage in oxides, will be done using X-ray spectro-microscopy techniques including X-PEEM, STXM, holography and ptychography at leading synchrotrons - Diamond (UK), PSI (Switzerland), Soleil (France) etc. We also employ quantum NV-magnetometry, in collaboration with the Mete Atature group (Cambridge), to perform stray field imaging.
Ultra-fast Dynamical Imaging: Time-resolved nanoscale dynamics will be captured using cutting-edge pump-probe X-ray imaging at synchrotrons – BESSY (Germany), PETRA (Germany) and Free Electron Lasers – FERMI (Italy), SwissFEL (Switzerland). Frequency-resolved dynamics will be captured with pump-probe micro-focus Brillouin Light Scattering.
Simulations and Theory: Dynamical evolution of magnetic states will be modelled using Oxford’s high-performance computing service (ARC). We use both atomistic and micromagnetic software [8]. Students will also collaborate with the leading theory expert Olena Gomonay (Mainz) to develop analytical solutions.
Students will have opportunities for extended stays with our world-leading collaborators: Paolo Radaelli (Oxford), Susie Speller (Oxford), Manuel Bibes (France), Dirk Grundler (Switzerland), and Ariando (Singapore).
If you want to join our team, contact Hariom Jani (hariom.jani@materials.ox.ac.uk) with your CV and a statement of interest.
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Project 2: Decoding antiferromagnetism with light: towards nanoscale optical readout
Supervisors: Hariom Jani and
Can we use light to design and read magnetic information at the nanoscale? This project will investigate how advanced optical techniques and quantum materials engineering can be combined to control and detect antiferromagnetic states, enabling new approaches to harness magnets through enhanced light-matter interactions.
Motivation: Antiferromagnets are an emerging class of quantum materials that could enable future information technologies. They host exceptional properties, including robust magnetic states, extremely fast dynamics and negligible stray fields. These properties unlock exciting opportunities for compact, high-speed and energy-efficient information processing. Recent advances have demonstrated that light can be used to manipulate and design antiferromagnetic order, opening new possibilities for optically programmable antiferromagnetic devices. However, a major challenge remains: how can we reliably read the information encoded in antiferromagnets? Antiferromagnets have a unique configuration containing anti-parallel spins. This makes conventional magnetic detection difficult, motivating new optical approaches that can reveal otherwise hidden magnetic order.
Project Scope: A central aim is to develop new pathways to read out antiferromagnetic states and excitations with nanoscale precision using light. This project will initially focus on α-Fe2O3 (hematite), a model antiferromagnetic oxide with a rich landscape of magnetic phases, spin excitations, and topological textures.
You will learn to design high-quality antiferromagnetic films and freestanding membranes. These engineered materials will provide a platform for investigating how distinct antiferromagnetic configurations influence optical responses. Using advanced optical microscopy and spectroscopy, including scattering, luminescence, linear and nonlinear optical techniques, you will investigate how light interacts with magnetic, electronic and vibrational degrees of freedom. Building on these insights, the project will explore plasmonically enhanced optical techniques to push the sensitivity and spatial resolution of antiferromagnetic detection to the nanoscale limit.
The project sits at the intersection of materials science, condensed-matter physics, ultrafast and nonlinear optics, plasmonics and spintronics. You will gain interdisciplinary training across the full experimental cycle: from engineering thin films and membranes to advanced optical spectroscopy, nonlinear optical microscopy and ultrafast measurements.
The project will combine the complementary expertise of the Jani group in quantum materials design, thin-film growth and magnetic-state engineering with the Di Martino group in nanoscale, nonlinear and ultrafast optical characterisation. Di Martino group has pioneered the optical interrogation of matter at the nanoscale, leveraging plasmonic light confinement to reveal otherwise inaccessible light–matter interactions and local material properties [, , ]. The Jani group has pioneered the discovery and control of nanoscale antiferromagnetism at room temperature, by leveraging quantum materials engineering [, , ].
Impact: The project will explore both the fundamental physics of light-matter interactions in antiferromagnets and their potential technological implications. Ultimately, understanding how magnetic states can be controlled and detected with nanoscale precision using light. This will enable new approaches to ultrafast and low-energy information technologies, with potential applications in spintronics, magnetic memory and unconventional computing.
Who are we looking for: We are looking for highly motivated applicants from physics, materials science or related disciplines, with a strong academic track record, solid communication skills and strong exposure to hands-on research. You do not need to have experience in all of the above areas of research, but you should be ready to learn on the go. Curiosity, creativity and passion for interdisciplinary experimental research are most important. If you want to join our team, contact Hariom Jani (hariom.jani@materials.ox.ac.uk) with your CV and a statement of interest.
References:
[1] J Grollier et al. Nature Electronics 3, 360 (2020).
[2] H Jani et al. Nature 590, 74 (2021).
[3] H Jani,* J Harrison* et al. Nature Materials 23, 619 (2024).
[4] A Tan,* H Jani,* et al. Nature Materials23, 205 (2024).
[5] H Jani, et al. Nature Communications 12, 1668 (2021).
[6] F Chmiel et al. Nature Materials 17, 581 (2018).
[7] J Harrison, H Jani et al. Optics Express 32, 5885 (2024).
[8] J Harrison, H Jani et al. Physical Review B 105, 224424 (2022).
[9] ZS Lim,* H Jani* et al. MRS Bulletin 46, 1053 (2021).