| December 12, 14:30
Superconductivity in Fe-based superconductors: competing orders and pairing fluctuations
The discovery of superconductivity in Fe-based superconductors in 2008 with Tc
reaching almost 60K is among the most significant breakthroughs in
contemporary condensed matter physics. The experimental data on
superconductivity show rich behavior, with potentially different symmetry of a
superconducting state for different compositions of the same material.
Furthermore, the phase diagram reveal a complex interplay between magnetism
and superconductivity typical for other exotic superconductors such as cuprates
or heavy fermions. In my talk I will present an introduction to various aspects of
the theory of iron-based superconductors. In particular, I will discuss general
aspects of the Cooper-pairing in Fe-based superconductors. I will argue that the
physics is universal and that all pairing states obtained so far can be understood
within the same universal pairing scenario. Then I will review the magnetic
ordering in the iron-based parent compounds. I will first analyze the selection of
the experimentally observed magnetic order out of the degenerate manifold
which occurs due to frustration associated with multiple nesting wave vectors. In
addition, in analogy to the J1-J2 model of the localized spins, I will discuss the
possibility of an Ising nematic order to form above the actual Neel temperature
and its coupling to orbital and lattice degrees of freedom.
Ruhr-Universität Bochum
Seminarraum des II. Physikalischen Instituts
Contact: not specified