# Physics & Astronomy Colloquium
3:30 PM, Friday, March 27, 2015
Room 155, Chem-Phys Building
** Dr. Shinsei Ryu **
University of Illinois, Urbana
**Topological crystalline insulators and superconductors; free fermion
classification and beyond
**
The importance of an interplay between topology and symmetries has been
recognized over
years since the discoveries of time-reversal symmetric topological
insulators. While initially
the effects of non-spatial symmetry such as time-reversal symmetry have
been focused,
it has been becoming clear that spatial symmetries such as reflection
symmetry and
point group symmetries also give rise to interesting topological phases
of matter, including
“crystalline topological insulators”. More generally, symmetry-protected
topological phases
of matter, i.e., phases of matter that are not adiabatically connected
to a trivial
phase such as an atomic insulator once a symmetry condition is enforced,
has been widely
discussed.
In this talk, I plan to overview recent developments in phases of matter
with reflection symmetry
(parity symmetry) with and without interactions. For non-interacting
fermion systems, I will discuss a systematic
classification of topological phases in a manner similar to the periodic
table of topological
insulators and superconductors (also known as “10-fold way”). I will
also discuss how interactions
modify the free fermion classification.
Refreshments will be served in CP 179 at 3:15 PM |