Abstract:

As a new concept to classify the states of matter, topology was introduced into the condensed matter physics in the 80’s last century. After the discovery of topological insulator, the interplay between topology and magnetism in the realistic materials attract lots of attentions. In this talk, I will focus on two parts. One is about the interplay between ferromagnetism and topology in magnetically doped TI thin films. We found a magnetic phase transition induced by the topological phase transition; and proposed a future spintronic device based on this discovery. One the other hand, we discovered that the Dirac fermions could exist in one type of antiferromagnetic (AFM) system, as long as in which the combination (PT) of time reversal symmetry and inversion symmetry survived. More importantly, by using the first principles calculations, we discovered that orthorhombic CuMnAs and CuMnP, one kind of compounds that have been experimentally synthesized were good candidates to host AFM Dirac fermions in 3D bulk states. This work explored the Dirac physics in the AFM system for the first time, and proposed real material candidates.

Bio:  汤沛哲：男，1987年生于甘肃兰州。2005年本科毕业于兰州大学，同年保送清华大学物理系攻读博士学位。2015年一月博士毕业于清华大学物理系，同年三月赴美国斯坦福大学，张首晟教授研究组从事博士后研究至今。主要研究领域包括利用第一性原理计算等方法研究拓扑材料与磁性的相互作用，寻找新型拓扑材料等。现发表文章23篇，包括Nature physics，Science，PRL等。