Wednesday, October 31, 2018
4:00 PM - 5:00 PM
Spalding Laboratory 106 (Hartley Memorial Seminar Room)

Materials Science Research Lecture

Magnetism, Superconductivity and Non-trivial Topology in Quantum Materials
Ni Ni, Assistant Professor, Condensed Matter, UCLA,

Abstract: New materials are the driving force for technology innovations and our progressive understanding in condensed matter physics. In the last decade, a breakthrough has been made on two material systems: high-temperature superconductors and three-dimensional topological materials. For the former, Fe based superconductors were discovered, joining cuprates and becoming the 2nd member in the high-temperature superconductor club. For the latter, the discovery of bulk materials with non-trivial topology has led to rich new emergent phenomena, including Fermi arc surface state, chiral pumping effect, colossal photovoltaic effect, etc.


In this talk, I will present the exciting progress in both directions. I will first go through how the chemical doping and external pressure tune the competing structural, magnetic and superconducting orders in the newly discovered 112 Fe pnictide superconductors. Then I will show the discovery of a "hydrogen atom" topological nodal line semimetal where two nontrivial bulk bands touch along a line and no trivial bands exist at the Fermi level.

More about the Speaker:  Prof. Ni got her Ph.D degree in Physics from Iowas State University in 2009. She worked on rare earth intermetallics and Fe pnictide superconductors in Paul Canfield's group during her PhD study. From 2009 to 2012, she was a postdoctoral researcher working with Bob Cava on layered magnets at Princeton. She became a Marie-Curie distinguished postdoctoral fellow in Los Alamos National Lab, working with Filip Ronning on heavy fermion materials before she became an assistant professor at UCLA in 2013.

 

*Refreshments will be served in the Spalding Laboratory lobby at 3:45pm

For more information, please phone 626-395-8124 or email jennifer@caltech.edu or