Sven Friedemann

This PhD project at the University of Bristol focuses on high-temperature superconductivity in nickel-oxides, specifically the recently discovered La3Ni2O7, which represents a new class of unconventional superconductors alongside cuprates and iron-pnictides. The research aims to understand the mechanisms behind superconductivity in these materials, with a particular emphasis on electronic interactions and the conditions that enable superconductivity at or above ambient temperatures. The project involves experimental studies including transport, magnetic, and crystallographic measurements to extract key superconducting parameters such as coherence length, London penetration depth, critical current density, and the nature of the superconducting gap. The work will also explore whether multiple gaps exist in the superconducting state, providing insights into the pairing mechanisms. The project benefits from close collaboration with Dr Dharmalingam and Prof. Boothroyd at the University of Oxford, leveraging expertise in crystal growth and high-pressure studies. Students will have the opportunity to work with novel nickelates synthesized in both Bristol and Oxford, aiming to discover materials that exhibit superconductivity at ambient pressure through chemical structure tuning. The School of Physics at Bristol offers a vibrant research environment, with a strong track record in research excellence and a supportive graduate community. Scholarships for home students cover living expenses, tuition, and training, while a limited number of fully-funded places are available for outstanding international candidates. Applicants should have a strong background in physics or a related field, and meet the University's English language requirements. The application process involves submitting a CV, personal statement, and transcripts, with early application encouraged. The deadline for applications is 19 January 2026. The School of Physics is committed to diversity and equality, encouraging applications from under-represented groups.

This PhD project at the University of Bristol's School of Physics focuses on investigating the strange-metal phase in cuprate superconductors using high-pressure techniques. Cuprate superconductors are known for their record-high transition temperatures at ambient pressure, but the underlying mechanism of superconductivity remains elusive. Traditional theories rely on coherent electronic states forming Cooper pairs, but recent research suggests that incoherent electronic states may also play a significant role. The project aims to study the crossover from the strange-metal phase, characterized by incoherent electronic transport, to the standard Fermi-liquid behavior of coherent quasiparticles. By applying high pressure to high-quality samples, the research will preserve material purity and reveal intrinsic behaviors, potentially uncovering the missing link between the strange-metal phase and normal metal Fermi liquid. The successful candidate will use electrical transport measurements to map coherent and incoherent contributions, analyzing resistivity, magnetoresistance, and Hall effect data. The project is supervised by Dr. Sven Friedemann and Professor Nigel Hussey, with support from J Buhot, and involves collaboration with international facilities such as the European High Magnetic Field laboratories. The School of Physics at Bristol offers a vibrant graduate research community, comprehensive induction and training programs, and strong support for diversity and career development. Funding is available for home students, covering living expenses, tuition, and training, with a limited number of fully-funded places for outstanding international candidates. Applicants should have a strong background in physics or a related field and meet the university's English language requirements. The application deadline is January 19, 2026. For more information, contact the Bristol Physics Graduate School at [email protected].

This PhD project at the University of Bristol's School of Physics focuses on studying high-temperature superconductors using advanced quantum sensors, specifically nitrogen-vacancy (NV) centres in diamond. The research aims to address key challenges in understanding unconventional and conventional superconductors, such as hydrides and nickelates, which exhibit superconductivity at high pressures. A major goal is to investigate spatial variations in critical temperature and correlate these with material composition and structure, using high-resolution mapping techniques. NV centres, which are atomic-scale defects in diamond sensitive to local magnetic fields, will be employed to probe superconducting properties at the microscopic level. These sensors allow for optical readout and can be integrated into high-pressure experiments. The project will also utilize synchrotron x-ray diffraction, Raman scattering, and bulk transport measurements to provide complementary spatially-resolved data. Another focus is on measuring the lower critical field of clean superconducting samples, which provides insight into the mechanisms of superconductivity and quantum phase transitions. The research is highly collaborative, involving Dr Sven Friedemann (expert in high-pressure measurements) and Dr Krishna Coimbatore Balram (expert in NV centre quantum sensors). Students will have opportunities to work at Bristol and participate in experiments at national and international synchrotron facilities. The School of Physics offers a vibrant graduate research community, comprehensive induction, targeted skills training, and strong support for diversity and career development. Funding is available for home students (covering stipend, tuition, and training), with a limited number of fully-funded places for outstanding international candidates. Applicants should have a strong background in physics or a related field, and meet the University's English language requirements. The application deadline is 19 January 2026. For more information, contact the Bristol Physics Graduate School at [email protected].