LASSP & AEP Seminar: Chenhao Jin (UC Santa Barbara)

Description

Long Lived Isospin Excitations in Flatband Graphene

A plethora of correlated many-body phases have been reported in flatband graphene systems. However, the dynamics associated with these correlated states, crucial for understanding the underlying physics, remains unexplored.

In this talk, I will discuss our recent efforts in investigating dynamics of isospin orders in flatband graphene systems by combining exciton sensing and optical pump-probe spectroscopies. With the capabilities of tracking melting and recovery of isospin orders at sub-picosecond resolution, we unveil the presence of abnormally long-lived isospin modes in magic-angle twisted bilayer graphene (MATBG) that decouple from the much faster cooling of electronic temperature, implying strong isospin fluctuations.

We further demonstrate ultra-fast control of the isospin orders, paving the way for actively controlling non-equilibrium phenomena in moire' systems.