Nan Xu
Ecole Polytechnique Federale de Lausanne, Switzerland
Title: Visualizing topological quantum states by photoemission spectroscopy: from topological kondo insulator to weyl semimetal
Biography
Biography: Nan Xu
Abstract
Recently, significant advances in topological theory extend the topological classifications from non-interacting insulators to strongly correlated insulators, and further to semimetals. In this talk, I will report our recent works about direct visualizations of topological quantum states with angle-resolved photoemission spectroscopy (ARPES), including:
- The observation of energy-band dispersions [1-2] and spin texture [3] of the metallic surface states on SmB6 as compelling evidences for the predicted strongly correlated topological kondo insulator states.
- Experimental realization of Weyl semimetal states in TaAs by direct observation pairs of 3D Weyl cones in the bulk states [4], matching remarkably well with our first-principles calculations.
- Experimentally realization of ideal Weyl semimetal state in TaP, where only single type of Weyl fermions contributing the exotic transport properties [5].
- Discovery first type-II Weyl semimetal state in MoTe2 in wihch Fermi surfaces consist of a pair of electron- and hole- pockets touching at the Weyl node and Weyl fermions strongly violate Lorentz invariance [6].
- Preliminary results on new topological quantum states.