University of Minnesota
School of Physics & Astronomy

Spotlight

Probing the nematic phase

Jian Kang
Jian Kang
Richard Anderson
                                                       

One of the goals of superconductor research, apart from understanding the physics phenomena, is to discover ways to enhance the transition temperature in superconductors so that they can be made more practical for use in devices. Jian Kang is a postdoctoral researcher, working with Professor Rafael Fernandes in the area of iron-based superconductors. Kang is a theoretical physicist whose research is particularly to understand the mechanism of high Tc superconductors.

Most iron-based superconductors have what is called a nematic phase. The term nematic comes from the study of liquid crystals, where the phenomenon was discovered. The nematic phase is one in which the molecules loosely arrange themselves in long strands, like threads, parallel to one another but not overlapping in layers. One of the properties of this phase is that the material has a preferred rotation. Kang has used numerical calculations to study the way that magnetism effects the nematic phase in the hope of being able to increase the transition temperature in iron-based superconductors.
Kang’s calculations have made two conclusions about the nematic phase. The first is that the nematic phase can enhance the transition temperature. The second is that the superconductivity gap structure is different in the nematic phase when s and d waves are mixed. Kang also have proposed experiments on measuring anisotropic penetration depth to testify his theory.