Research

Competing/coexisting phases in high temperature superconductor systems

Since high temperature superconductivity (HTSC) has been discovered in copper oxides in 1986, tremendous research efforts have been devoted to understand its mechanism. Yet even after more than 25 years, it still remains as one of the most challenging and interesting problems in physics. In more recent years, another family of superconducting materials, so called Fe-based superconductors have got a great attention. The Fe-based system marked the second highest superconducting transition temperature after cuprates and rich variants of materials show superconductivity. In both systems is the superconductivity hosted by a 2 dimensional plane and magnetically ordered phases are found in the vicinity of the superconducting dome. One of the most fascinating aspects is that both systems present rich phase diagram with competing orders, at the boundary of which quantum phase fluctuation may work for the superconductivity. These facts have made researchers believe that proper comparisons of the two superconducting systems should lead us to the mystery of high temperature superconductivity.

We aim to reveal details of phase coexisting and competing behaviors in cuprates and Fe-based superconductors by means of ultrafast broadband pump-probe study.

Others projects:

In addition to studies focused on the superconductivity, various projects, such as nonlinear pump-probe responses of Mott insulators, charge density wave systems and magnetic/ferroelectric/multiferroic materials, are under going.