###Polaronic structures and properties in High Tc superconducting oxides
Project ID: 2228bd1171 (You will need this ID for your application)
Research Theme: Advanced Materials
UCL Lead department: Chemistry
Lead Supervisor: Richard Catlow
Project Summary:
Despite over 30 years intensive study, the origin of high-temperature superconductivity in oxide materials remains controversial, with uncertainty as to the basic mechanisms and to the nature of the charge carriers. In an early study, Catlow and Islam (J. Phys. Condensed Matter, 10, L49, 1998) proposed that hole states in the prototypic doped La2CuO4 high Tc material were predominantly of O 2p character and would couple to form a “peroxy bipolaronic” species which could act as charge carriers. Renewed interest in this model is evident from the recent review of Edwards and coworkers (J. Solid State Chemistry, 317, 123539, 2023). It is timely therefore to return to the nature of charge carriers in these materials using the quantum mechanical/molecular mechanical (QM/MM) techniques now available in the ChemShell code, whose development has been led by the Daresbury computational science and engineering team in collaboration with UCL and which are ideally suited to this problem. The project will include methodological development and code implementation within ChemShell to address the need for accurate models of local excited states in complex materials. Incorporation of the material’s response to light in the embedding model will form the essential challenge of the student’s project, addressing which will allow the nature of the charge carriers to be unravelled and determine their stability, spectroscopic signatures and transport properties. Software development will centre on the problem of coupling electronic and vibrational degrees of freedom in polarons and bipolarons based on the vibrational (VSCF) and optimisation (DL-FIND) module of ChemShell. The project will provide the student with an excellent training in contemporary materials chemistry and physics and in the computational techniques employed in the field. It will also provide valuable skills in software development. Students with backgrounds in either chemistry, physics or materials science will be suitable for this project.