报告题目：Three-dimensional quantum Hall Effect and Metal-Insulator transition in ZrTe₅

报 告 人：Liyuan Zhang, Professor, Southern Univeristy of Science and Technology

报告时间：2018-05-07 09:00

报告地点：理科楼郑裕彤讲堂

报告摘要：The discovery of quantum Hall effect had greatly improved the understanding of the phase transitions and topological orders in two-dimentional systems. It is natural to ask whether there are similar phemomena that might occur in three-dimentional systems. However, the long-sought three-dimensional (3D) quantum Hall effect has not been well experimentally demonstrated. Here we report an experimental observation of three-dimensional quantum Hall effect in zirconium Penta-telluride（ZrTe₅）within a magnetic field B (<1 .3t). from the shubnikov-de-haas oscillation in three orthogonal crystal directions, we find a π berry phase in one plane while zero in the other two planes, strongly suggesting that the zrte₅bulk is a weak topological insulator. By combining Hall measurement, we discover that each Quantum Layer contributes 2e²/h with a thickness of one Fermi wavelength λF in b direction. As further increasing magnetic field, the system has reached the Quantum Limit regime, where the resistance R_xx(B) increases dramatically and displays Metal-Insulator transition behavior. With analysing Rxx(B) scaling plots, we confirm this Metal-Insulator transition is a many-body quantum topological phase transition. Our finding not only provides a new understanding of the interplay between 2D and 3D Landau quantization but also allow for the further exploration of the higher dimensional electronic gas system and exotic strongly corrected topological phase transitions.