Dechen Zhang

A major goal in condensed matter physics is to find a magnetic system where quantum spins behave like free particles—specifically, separating into neutral excitations called spinons, similar to how electrons can split into fractions in the quantum Hall effect. This long-sought state, called a quantum spin liquid, has remained largely theoretical.

Abstract While the surface-bulk correspondence has been ubiquitously shown in topological phases, the relationship between surface and bulk in Landau-like phases is much less explored. Theoretical investigations since 1970s for semi-infinite systems have predicted the possibility of the surface order emerging at a higher temperature than the bulk, clearly illustrating a counterintuitive situation and greatly enriching phase transitions.

Abstract The thermal Hall effect recently provided intriguing probes to the ground state of exotic quantum matters. These observations of transverse thermal Hall signals lead to the debate on the fermionic versus bosonic origins of these phenomena. The recent report of quantum oscillations (QOs) in Kitaev spin liquid points to a possible resolution. The Landau level quantization would most likely capture only the fermionic thermal transport effect.