Liang Fu: Doping and Inverting Mott Insulators on Semiconductor Moire Superlattices

"Doping and Inverting Mott Insulators on Semiconductor Moire Superlattices"

Abstract: Semiconductor bilayer heterostructures provide an ideal platform for simulating Hubbard models on an emergent lattice defined by moire potential minima. As a hallmark of Hubbard model physics, the Mott insulator state has been observed at half filling of moire band. In this talk, I will describe new phases of matter that grow out of the canonical 120-degree antiferromagnetic Mott insulator on the triangular lattice. First, doping this Mott insulator under a certain range of magnetic fields gives rise to a dilute gas of spin polarons, which form a pseudogap metal and result in a doping-dependent magnetization plateau. Second, the application of an electric field between the two layers can invert the many-body gap of a charge-transfer Mott insulator, driving a (continuous) phase transition to a Chern insulator with a chiral spin structure. Experimental results will be discussed and compared with theoretical predictions.

Biography: Liang Fu is a Professor of Physics at MIT. He obtained a Bachelor’s degree in Physics from the University of Science and Technology of China in 2004 and PhD in Physics from the University of Pennsylvania in 2009. He was a Junior Fellow at Harvard University before joining the MIT faculty in 2012.