Emergent electronic properties of strain tuned superconducting materials

Dr Luke Rhodes
Research Fellow 2019

Dr Luke Rhodes
University of St Andrews

Superconductivity, the ability to carry electric currents with zero resistance and loss, has the potential to radically transform our capacity to generate, transport and use electrical power. The main impediment is the low temperatures of -250 degrees Celsius required to reach this state. The few superconductors which have this property at substantially higher temperatures, the so-called high-temperature superconductors, are still poorly understood and the mystery behind why these materials become superconducting remains one of the largest unsolved problems in condensed matter physics. Solving this puzzle promises new routes to design superconductors with higher transition temperatures or tailored properties for specific applications.

Recent experiments have demonstrated that the application of a relatively small amount of strain to certain superconductors can have an unexpectedly large effect on the superconducting transition temperature, as well as induce an abundance of closely related exotic properties. This hints at the importance of electron-lattice coupling within strongly correlated superconducting materials, however, the interplay between these emergent properties and the electron-lattice coupling is not well understood. I wish to pursue a cross-disciplinary approach, combining real space imaging, theoretical modelling and photoemission experiments to gain fundamental insight into the nature of strain-tuned superconducting materials.

"This research may provide a pathway for raising the transition temperature of high-temperature superconductors"

The study of materials under strain has so far been limited due to the technical challenge of developing a device which is compatible with the often unique experimental machinery. Recently, the ability to study materials under strain using both real space imaging and photoemission has been developed at the University of St. Andrews. By using my previous theoretical and experimental knowledge of these complementary techniques, I will perform experiments on superconducting materials under strain and combine the results via a bespoke theoretical framework that I have previously developed. This project, therefore, offers a unique opportunity to provide close collaboration between two independent experimental techniques, supported by theoretical calculations, all within the same institution.

This ambitious research aims to greatly improve our understanding of strain tuned superconducting materials which may provide fundamental information on electron-lattice coupling in strongly correlated quantum materials and provide a pathway for raising the transition temperature of high-temperature superconductors.