Condensed Matter Seminar

Graphene is not the only two-dimensional material with far-reaching significance. It falls into the category of van der Waals (vdW) materials which can be exfoliated down to atomically thin monolayers. Thousands of them have been created and can be further assembled into designer heterostructures like quantum Lego. Stackings can induce moiré patterns, sparking major efforts in the studies of resultant new electronic phenomena in vdW heterostructures.

Abstract:
With the advancements in quantum materials research, the emergent quantum many-body phenomena, such as competing orders, topological order and fractionalization, can be realized in much more controllable ways. However, resolving them experimentally can be challenging.

 

Abstract
Quantum many-body theories, including diagrammatic perturbation theory and non-perturbative embedding theories, are rigorous and well-developed theories used to describe the physics of many interacting particles in solids. They are typically applied to lattice model systems that capture only the essential degrees of freedom.

Abstract:
In this talk, I will discuss a number of basic issues associated with phonon chirality, such as the angular momentum carried by circularly polarized phonons, electronic magnetization induced by such phonons, and the creation of phonon chirality from time reversal symmetry breaking.  

 

 

Prof. Niu is a renown theoretical physicist and has made many pioneering contributions to studies of Berry phase effects, topological properties, and spin transport properties.