Welcome to the topological matter theory research group at Columbia University. We investigate quantum phenomena of condensed matter systems and are fascinated with symmetry and topology. We explore how topology crucially influences fundamental characteristics of solid-state materials.
Tuning the speed to of Dirac fermions to zero
In our recently published paper we show that Dirac fermions do not like to get their speed to zero, unless they really have to. Knowing how many knobs we need to fine-tune lays the foundation to find new topological flat bands with the possibility for exotic correlated phases:
Five years of superconductivity in magic-angle graphene
New demonstrations of superconductivity in multilayer stacks of graphene continue to emerge, even as researchers struggle to explain how it all works.
Princeton PCCM Summer School 2022
Lecture 1 "Topological obstructions in real space - atomic bands"
Lecture 2 "Topological obstructions in real space - topological bands"
And photos here, thank you to the organizers for a great school!
Classification of topological matter
Topological phases appear in many forms and shapes. We strive for a exhaustive understanding of the topology of condensed matter systems, studying novel phases, novel invariants and boundary signatures.
Disordered topological matter
Dirt and impurities are unavoidable in real physical systems. They break translation symmetry and invalidate Bloch's theorem. But can we still find order in disorder? Are there topological invariants that subside these harsh conditions?