Navinder Singh

• Anomalous electronic transport in the strange metal regime of (un)conventional superconductors
• Theory of (un)conventional superconductivity (i.e.in Cuprates, heavy fermions, and Fe based compounds)

ELECTRONIC TRANSPORT IN STRANGE METALS:: Electronic transport in simple metals can be understood using quasiparticle concept and the Bloch-Boltzmann kinetic theory. However, in strange metals (like, normal states of Cuprates, heavy fermion, and iron based superconductors) electronic transport mechanisms remain elusive. We are interested in such cases, and the Mori-Zwanzig memory function formalism can provide partial answers. However, the problems remain open.
A very basic introduction is given in:

THEORY OF (UN)CONVENTIONAL SUPERCONDUCTIVITY (i.e. in Cuprates, heavy electron materials, and Fe based compounds) Theory of conventional superconductivity known as BCS (Bardeen-Cooper-Schrieffer) theory is successful in explaining the superconducting behaviour of some metals and simple compounds. It cannot be applied to cuprates and Fe based compounds (called high temperature superconductors) as the pairing mechanisms in these new compounds are not due to phonons and it does not have an adequate foundation as normal state of these compounds shows non-Fermi Liquid behaviour. Understanding the physics of cuprates and Fe based compounds represent a long-standing and challenging problem in condensed matter physics. These materials are very poor conductors of electricity in their normal state but become superconducting at very high temperatures in comparison to conventional superconductors. Despite over 3 decades of research on the cuprates, a comprehensive microscopic theory does not exist and there is no consensus on their underlying pairing mechanism.