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PhD, MSc, & Postdoctoral Opportunities

Research Fellows

At present the Group has no positions open for research fellows. If you would like to apply for a fellowship hosted here at Warwick, please contact one of the permanent members of academic staff.


PhD Projects

Every year at least one studentship is available for a suitably qualified applicant to join our Group. Early applications for places are strongly encouraged. Details of the projects currently available are given below. For more details of the kind of work carried out by the students in our Group please refer to the PhD current research projects page.

PhD Project Titles - (Note, any funding is only likely to be available for UK/EU nationals)

New classes of quantum material studied using ultra-high magnetic fieldsLink opens in a new window
Supervisor: Paul Goddard

Many of today's most interesting, innovative and potentially useful materials display states of matter explicable only by applying quantum mechanical models that are on the edge of our current understanding. This is unsurprising as these quantum materials are typically host to a complex network of many-body interactions between spins, electrons and phonons, and are exquisitely sensitive to aspects such as dimensionality, quantum fluctuations and topology. The states that emerge from this microscopic soup frequently exhibit cooperative properties (superconductivity, charge or spin-order, multiferroicity) or exotic excitations (magnetic monopoles, skyrmions, Majorana fermions) of considerable fundamental interest. Understanding these properties and perhaps harnessing them for use in next generation magnetic and electronic devices, sensors and actuators is one of the most pressing challenges facing modern physics.

As well as investigating new examples of inorganic materials showing novel conducting and magnetic states of matter, this PhD project will build on recent de- velopments whereby non-ionic chemical bonding produces of new types of quan-tum material with properties not seen previously.

Recent examples of quantum materials. (a) The spin-1/2 antiferromagnetic chiral chain [Cu(pyrazine(H2O)4]SbF6H2O. This is a deeply quantum system that is found to display as yet unexplained behaviour in an applied magnetic field [1]. Inset shows a single crystal of the material. (b) Magnetic quantum oscillations (top) observed in ac frequency measurements of the strongly correlated semi-metal CeOs4Sb12. The enhancement of the charge carrier effective mass (bottom) points to a hidden quantum critical point around 20 T [2]. (c) Inelastic neutron scattering on the highly one-dimensional spin-1 chain NiI2(3,5-lutidine)4. The peaks at 0.5 and 0.7 meV show an energy gap developing at low temperature as a direct result of the integer spin of the Ni(II) ions [3].

[1] J. Liu, et al., Phys. Rev. Lett. 122, 057207 (2019).
[2] K. Gotze et al., Phys. Rev. B 101, 075102 (2020).
[3] R. Williams et al., Phys. Rev. Res. 2, 013082 (2020).


Chiral and Skyrmionic Magnetic Materials

Supervisor Geetha Balakrishnan, Co-supervisor Martin Lees

The recent discovery of skyrmions in magnetic materials and of their self organisation into a skyrmion lattice together with their potential use for magnetic storage has made skyrmion physics one of the hottest topics in magnetism research.

A PhD studentship is available starting from October 2019 to work on chiral magnets and skyrmionic materials, including materials which have previously been identified to exhibit skyrmionic behaviour, as well as exploring new materials which may exhibit this behaviour. The project will make use of a number of experimental techniques to synthesize the crystals and will encompass the study of the crystals produced through detailed investigations of their structural and magnetic properties. The project will involve several collaborations with research groups both within the UK and Internationally. To complement our in-house studies, there will also be scope for taking part in experiments at international facilities using neutrons, muons and synchrotron radiation.
The project takes place in the context of a wider programme of materials investigation currently underway within the Superconductivity and Magnetism Group in the University of Warwick. Warwick is one of the five consortium universities in the UK National Research Programme on “Skyrmionics: From Magnetic Excitations to Functioning Low-Energy Devices”, funded by EPSRC, UK, involving the universities of Durham, Oxford, Cambridge and Southampton. Industrial partners are also involved.

This is a new, exciting and fast moving field and an ideal project for a strong and enthusiastic student. The student will be enrolled on the Materials Physics Doctorate scheme (go.warwick.ac.uk/MPDOCLink opens in a new window).

Topological Insulators

Supervisor Geetha Balakrishnan, Co-supervisor Martin Lees

Topological Insulators (TIs) have been hailed as a new state of matter. TIs are materials that are insulating in the bulk, but exhibit special surface states that are conducting and topologically protected-i.e. the spin-orbit coupling in these materials leads to the formation of surface states that cannot be destroyed by scattering or impurities. Following the discovery of topological behaviour in the 2-D HgTe systems, several new 3-D materials exhibiting topological behaviour have been discovered. The 3-D TIs are thought to hold immense potential and have been likened to graphene in their surface electronic properties, with great promise for technological applications in areas such as thermoelectrics, electronics, spintronics and quantum information processing to name just a few.

Although the TIs have gapless edge or surface states that are protected, and an insulating gap in the bulk, most of the 3-D TIs discovered to date are still fairly conducting in the bulk. The challenge has been to create TI materials that are true insulators in the bulk in order to enable the study of their exotic surface states. Materials design and preparation has emerged as being key to the investigation and the discovery of new and better TIs.

The study will involve the synthesis of high quality TIs and characterisation of the bulk properties to understand their importance in influencing the surface states. Emphasis will be placed on the investigation of the structural aspects, information from which will be used to design and fabricate potential materials with TI behaviour. The project will also involve work on several Topological Crystalline Insulators (TCIs), Topological Kondo Insulators as well as TIs that are superconductors, exhibiting a full pairing gap in the bulk and gapless surface states, in analogy with the TIs. Some experimental work on the production and study of new TIs/TCIs in the form of nanomaterials will also be attempted.

The project is part of a new EPSRC funded programme on Topological Insulators. The student will be offered valuable training in the synthesis, in-house characterisation and the use of neutrons and muons at central facilities for the study of the interesting properties exhibited by TIs. The student will also have the opportunity to be involved in several collaborations, both within Warwick (Electron microscopy, Structural studies, NMR and Nanoscience) and with various groups outside Warwick to perform ARPES and other experiments to investigate the exotic surface properties of these materials.

The student will be enrolled on the Materials Physics Doctorate scheme (go.warwick.ac.uk/MPDOC).

Frustration in Magnetic Oxides

Supervisor Martin Lees, Co-supervisor Oleg Petrenko

In simple magnetic materials the magnetic behaviour is usually governed by the strength and sign of the interactions between the magnetic moments in the system. In frustrated magnets the competing interactions between the moments cannot all be satisfied simultaneously.

Studies of frustrated magnetic oxides have resulted in the discovery of some exciting new physics including spin ice and monopoles (see Fig. 1). Many of these breakthroughs have opened new avenues of research, while others have raised important questions that remain unanswered. It is the physics of these systems that will be the focus of this project. For some of our recent work please see Refs. 1 to 3.

planar_exchange_coupling.jpg
In this project, you will use image furnaces to grow high quality single crystals of oxide materials. The structural properties of these frustrated materials will be studied using a suite of state-of-the-art x-ray spectrometers and electron microscopes. You will examine the magnetic properties of these crystals in the laboratory at low temperatures and in high magnetic fields. You will also use a range of neutron scattering and muon spectroscopy techniques at national and international central facilities to investigate the physics of these materials. Fig. 1. Phase diagram as a function of temperature T and the relative strength of the planar and Ising exchange for some pyrochlore titanates. Ho2Ti2O7 and Dy2Ti2O7 are spin ice while Yb2Ti2O7 undergoes a first-order transition from a Coulomb liquid to a Higgs phase of magnetic monopoles [1].

This experimental project will offer an excellent training in many aspects of modern condensed matter physics. The student will be enrolled on the Materials Physics Doctorate scheme (go.warwick.ac.uk/MPDOC).

[1] L.-J. Chang, S. Onoda, Y. Su, Y.-J. Kao, K.-D. Tsuei, Y. Yasui, K. Kakurai, M. R. Lees, Nature Communications 3, 992 (2012).
[2] S. Petit, E. Lhotel, B. Canals, M. Ciomaga Hatnean, J. Ollivier, H. Mutka, E. Ressouche, A. R. Wildes, M. R. Lees, G. Balakrishnan, Nature Physics 12, 746 (2016).
[3] E. Lhotel, S. Petit, M. Ciomaga Hatnean, J. Ollivier, H. Mutka, E. Ressouche, M. R. Lees, G. Balakrishnan, Nature Communications 9, 3786 (2018).

Unconventional Superconductors
Supervisor: Martin Lees, Co-supervisor Geetha Balakrishnan

In conventional superconductors, the superconductivity arises from an electron-phonon coupling of electrons to form Cooper pairs, with a single, s-wave, isotropic gap. In unconventional materials, the Cooper pairs may be coupled by other interactions, the pair wave function may be an odd-parity spin-triplet, or there may be multiple superconducting bands.

Unconventional superconductivity can be found in number of different classes of materials. These include superconductors with noncentrosymmetric crystal structures, i.e., systems without inversion symmetry where parity is no longer a meaningful label, in materials with strong spin-orbit coupling, e.g., those containing 4d and 5d metals, and in systems with unusual crystallographic geometries, e.g., kagome lattice superconductors. It will be these three groups of superconductors that will be the focus of this work. In unconventional superconductors, a variety of physical effects that may previously have been forbidden are now allowed. Examples include exotic superconducting gap structures (lines or nodes in the superconducting gap), upper critical fields exceeding the Pauli limit, time reversal symmetry breaking, and even topological effects. For some of our recent work in this area please see Refs. 1-8.

Working in the Superconductivity and Magnetism Group (go.warwick.ac.uk/supermag) you will learn how to prepare polycrystalline and single crystal samples. The structure and composition of the samples will be studied using a suite of x-ray diffractometers and electron microscopes. You will then examine the normal and superconducting state properties of these materials at low temperatures and in high magnetic fields. As well as experiments in our laboratories, a range of neutron scattering and muon spectroscopy techniques available at national and international central facilities will also be used to investigate the physics of these materials. This experimental project will offer you an excellent training in many important aspects of modern condensed matter physics.

This experimental project will offer you an excellent training in many important aspects of modern condensed matter physics. The student will be enrolled on the Materials Physics Doctorate scheme (go.warwick.ac.uk/MPDOC).

[1] R. P. Singh et al. Detection of time-reversal symmetry breaking in the noncentrosymmetric superconductor Re6Zr using muon-spin spectroscopy, Phys. Rev. Lett. 112, 107002 (2014).

[2] J. A. T. Barker et al. Unconventional superconductivity in La7Ir3 revealed by muon spin relaxation: introducing a new family of noncentrosymmetric superconductor that breaks time-reversal symmetry Phys. Rev. Lett. 115, 267001 (2015).

[3] J. A. T. Barker et al. Superconducting and normal-state properties of the noncentrosymmetric superconductor Re3Ta, Phys. Rev. B 98, 104506 (2018).

[4] D. A. Mayoh et al. Multigap superconductivity in chiral noncentrosymmetric TaRh2B2, Phys. Rev. B 98, 014502 (2018).

[5] P. K. Biswas et al. Chiral singlet superconductivity in the weakly correlated metal LaPt3P, Nature Communications 12, 2504 (2021).

[6] D. Das et al. Probing the superconducting gap structure in the noncentrosymmetric topological superconductor ZrRuAs, Phys. Rev. B 103, 144516 (2021).

[7] D. A. Mayoh et al. Evidence for the coexistence of time-reversal symmetry breaking and Bardeen-Cooper-Schrieffer-like superconductivity in La7Pd3, Phys. Rev. B 103, 024507 (2021).

[8] D. G. C. Jonas et al. Quantum muon diffusion and the preservation of time-reversal symmetry in the superconducting state of type-I rhenium, Phys. Rev. B 105, L020503 (2022).

Click hereLink opens in a new window for more details of the formal application procedures, the relevant application forms and a postgraduate prospectus. N.B. This information is mounted on the Physics Department web pages outside this Superconductivity and Magnetism site.


MSc Research Projects

We always have places available for suitably qualified self-funded students who would like to work towards an MSc. For more details of the kind of work carried out by the students in our Group please refer to the current postgraduate research projects page.

MSc Project Titles

Topological Insulators: Investigation of the bulk properties of new topological insulators and superconductors.

Supervisor Geetha Balakrishnan

Click hereLink opens in a new window for more details of the formal application procedures, the relevant application forms and a postgraduate prospectus. Note, this information is mounted on the Physics Department web pages outside this Superconductivity and Magnetism site.


Technical Posts

At the moment the Superconductivity and Magnetism Group has no vacancies for Technical Staff.


Useful Links

You may like to view the Warwick University Human Resources OfficeLink opens in a new window web page with a listing of all the jobs that are currently available here at the University.

Current vacancies at universities throughout the U.K. are listed on the jobs.ac.ukLink opens in a new window web site.

PhD projects

Click here to see a more details of the PhD projects available here in the Physics Department at Warwick.


Other external funding opportunities for postdoctoral staff

 

Marie-Curie fellowships (European Union funding)

EU Commission
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Royal Society fellowships

The Royal Society
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 Humboldt Foundation - Feodor Lynen fellowships (for German Post-docs)

closing dates: 10th February, 10th June, and 10th October

Alexander von Humboldt
Click here for more details