The discovery of superconductivity under ambient conditions would unlock the full potential of this remarkable phenomenon and allow technological developments that would help solve some of the most pressing and important societal challenges, such as reducing greenhouse gas emissions, transforming health and healthcare, and developing new quantum technologies, all of which are EPSRC research priorities. This experimental research proposal aims to probe the microscopic nature of high-temperature superconductivity in a class of materials known collectively as hydride superconductors and in so doing, will take critical steps towards achieving this important milestone. Electric currents can flow through superconductors without energy dissipation, i.e. without electric resistance, below a critical transition temperature Tc. This unique property is already exploited in medical applications such as MRI and encephalography, while superconducting qubits are considered as one of the most promising platforms for quantum computation. New applications to deliver cleaner energy are also under development. In nuclear fusion reactors (www.tokamakenergy.co.uk), for example, the high magnetic field strengths required to confine the hot plasma can only be produced by superconducting magnets. The main impediment to large-scale exploitation of superconductors in mainstream applications is simply the cost incurred in having to cool them down below Tc. This drives the continual search for better and more robust superconductors. The ultimate quest for room-temperature superconductivity has been one of the most intensely pursued topics in condensed matter physics. Recently, it has reached its peak with the discovery of several superhydride compounds such as H3S and LaH10 synthesised at ultra-high pressures. While near-room-temperature superconductivity has been confirmed in these compounds by a few independent research groups, no microscopic signatures of the superconducting state have yet been reported. Determining the fundamental parameters responsible for room-temperature superconductivity under such extreme pressures will help guide theoretical efforts to identify candidate materials that can support superconductivity under ambient conditions, i.e. at room temperature and at atmospheric pressure. Under the auspices of this Fellowship, I will aim to provide groundbreaking insights into the microscopic nature of the near-room-temperature hydride superconductors. I will develop a set of state-of-the-art experimental techniques, including Raman spectroscopy and tunnelling spectroscopy under extreme conditions of high pressures and high magnetic fields, to deliver quantitative measurements of the superconducting gap amplitude, as well as the energy spectrum of the relevant atomic vibrations and their coupling with electrons; all key parameters in controlling Tc. At the same time, I will work in close partnership with renowned theorists in the field, who will use my experimental inputs in their search for candidate structures and chemical compositions that could replicate the favourable conditions for achieving near-room-temperature superconductivity at lower applied pressures. In this way, progress towards large-scale exploitation of this transformational technology can be made.