"Topological phases, broken-symmetry orders and their competitions"

 

 

 

The essential goal of condensed matter physics is to understand how sextillions (10E21) of electrons are organized together and form electronic materials with useful properties. Two grand organizing principles are known to human being: The first is the more familiar broken-symmetry order, as was first realized by Lev Landau. And the other is called “topological order”, which explains recently discovered topological phases such as quantum Hall states and topological insulators. The physics becomes even more interesting in the so-called “correlated electron systems” where electron interaction is strong and different kinds of orders start to coexist and compete with each other. In this talk, I will use high temperature superconductor LBCO, topological Kondo insulator SmB6 and fractional quantum states near filling factor 5/2 as typical examples of strongly correlated electron systems. And I will describe some recent stories in my lab of detecting broken-symmetry / topological orders and studying their competitions in these materials. By extension, I will also describe a few potential applications that we are working on.