X-ray Absorption studies of metal hydrides under extreme pressure (XA-EXTREM) (2018 - 2020)

Project coordinator: Dr. Hab. Phys. Juris Purans

Leading participant:

Total cost: 200 000 EUR

Duration (years): 2018-2020

LZP FLPP No.LZP-2018/2-0353

Searching for new high temperature superconductors which could be used in everyday applications is nowadays one of the most important and challenging problems in physics and materials science. A huge step forwad has been made in 2015, when superconductivity has been discovered in hydrogen sulfide with the record-hight critical temperature Tc = 203K. Although the physical mechanisms responsible for superconductivity are known, more detailed experimental information about behaviour of the electrons and their coupling with the phonons is requied.  In this project we aim to obtain new information about  the evolution of the electronic and the local atomic structures  in hydrogen rich metal hydrides as temperature and pressure (200 GPa) are varied. We will apply the novel microbeam synchrotron-radiation based X-ray absorption fine structure (XAFS) technique at extreme pressure. The Y-H and La-H systems, will be examined where new hydrogen-rich phases are predicted to be formed with the Tc higher than in supfur hydride. The structural information obtained by advanced ab-initio XAFS analysis including including Reverse Monte Carlo will be compared with the theoretically predicted superconducting phases. The project is multidisciplinary and combines materials science, synchrotron radiation technique at extreme pressure, solid state chemistry, physics and computer science.