In this talk, I will mainly introduce our recent work on numerical study of Quantum Hall systems with half-filled Landau levels by exact diagonalization (ED) and density matrix renormalization group (DMRG) methods. In the first part, I will talk about the nature of the quantum Hall liquid in a half-filled second Landau level (n=1) as a function of band mass anisotropy. We find increasing the mass anisotropy induces a quantum phase transition from the Moore-Read state to a charge density wave state. In the second part, I will show the phase diagram of 1/2+1/2 quantum Hall bilayer systems of the lowest Landau level as a function of layer distances. We identify three distinct phases, including an exciton superfluid phase with spontaneous interlayer coherence at small distance, a composite Fermi liquid at large distance, and a new intermediate phase for intermediate regime.
Dr. Zheng Zhu has been working as a postdoctoral associate in the department of physics in MIT since 2015. He got his bachelor degree from the Department for Intensive Instruction at Nanjing University in 2010, and his PhD degree from the institute for advanced study at Tsinghua University in 2015. His research activities mainly focus on many-body problems in condensed matter by combining theoretical analysis and numerical simulation. Most of his research area belongs to the strongly correlated systems, including the physics of doped Mott insulators especially the high temperature superconductors, the fractional Quantum Hall states in two-dimensional electronic systems, and exotic states of matter in frustrated magnetic systems. He also has a lot experience on the computational condensed matter methods such as exact diagonalization (ED) and density-matrix renormalization group (DMRG) in strongly correlated systems.
Host: Prof. Canhua Liu canhualiu@sjtu.edu.cn