Structural instabilities in strongly correlated electron systems

Supervisor: Dr. Monika Gamza

Strongly correlated electron systems belong to the most intriguing and versatile materials. In these systems, competing interactions lead to the emergence of a multitude of exotic states, including unconventional superconductivity and magnetism, valence fluctuations, heavy fermions, Mott insulators, non-Fermi liquids, phases with charge stripes or a pseudogap. Here, subtle changes in chemical composition, pressure, temperature or magnetic field may tip the balance between the competing tendencies, resulting in huge responses to the stimuli. One example would be a colossal magnetoresistance, where enormous variations in resistance are produced by small changes in magnetic field strength. Another examples include temperature- or pressure-induced metal-insulator transitions. Thestrong competition between different phases is not only essential for applications, but it also increases the potential for novel electronic behaviour.

In this project, you will investigate selected intermetallic compounds in which strong coupling between charge, spin, orbital, and lattice degrees of freedomleads to complex phase diagrams. The project will start with growing crystals using flux method in the newly developed synthesis lab at UCLAN. Structural and compositional characterization of grown phases will be carried using instruments available in the UCLAN Analytical Suite. In the next steps, detailed investigations of crystal structure by means of X-ray diffraction, absorption (EXAFS) and/or pair-distribution function measurements over broad temperature ranges and/or under high pressure will be proposed at world leading research facilities, in a close collaboration with research groups from other universities. The experimental study will be supplemented by first principles computational simulations using state of the art electronic band structure codes such as FPLO or Wien2k.

The project is available for UK and EU students holding or expecting good undergraduate/postgraduate degrees in Physics, Chemistry or related subjects. For details on the project or application procedures please contact Dr Monika Gamza: MGamza@uclan.ac.uk