Transport, Interactions, and Flavortronics in 2D Transition Metal Dichalcogenides

Transition metal dichalcogenides (TMDs) provide a unique 2D material platform for discovering novel physics. First, I will briefly discuss our original predictions on the unconventional quantum Hall effect and “topological” valley Hall effect of massive Dirac fermions in monolayer TMDs, which have been confirmed by optical spectroscopy, quantum transport, and local compressibility measurements. Next, I will introduce our recent theories and experiments that have discovered the G-valley holes and Q-valley electrons in the quantum transport of few-layer TMDs. Particularly, the G-valley holes have an extremely large effective mass that produces an odd-integer predominated quantum Hall effect with giant spin susceptibility and extreme density sensitivity, prerequisites for the Wigner crystal phase. Finally, I will elucidate that the TMD Q valleys offer an unprecedented opportunity to realize the solid-state version of SU(3) flavor symmetry that is rare in electron systems. In the quantum-Hall regime, we have predicted that the spontaneous flavor symmetry breaking yields ferroelectric valley nematics tunable by an in-plane electric field. In the quantum-dot geometry, we have predicted flavor enforced irrational Coulomb peaks and fractional Kondo peaks. These effects lead to a new concept–flavortronics.