Angle-Resolved Photoemission Spectroscopy Study Of Topological Materials

Recently the discoveries of Fermionic particles in sold matters make condensed matter physics an attractive field.Both the theoretical predictions and the experimental discoveries have got the unprecedented successful achievements.In the high energy physics,there are just three free fermionic particles?Diarc fermion,Weyl fermion and Majorana fermion,limited by Poincare symmetry and Lorentz invariance.However,there are 230 space groups in condensed matters.Because of the various symmetries seem like 230 “Universes”,there must be more potential to find new kinds of fermions in solid states.Each quasi-particle fermion can be classified by one kind of topology.All of these make condensed matter physics a good field to study the basic physics.The topology of each material can be defined by one kind of invariance.The nontrivial material has a novel state with nonzero topological invariance and there always exists exotic surface states on the boundary.All of the characters make Topological materials unordinary in condensed matter physics.Topological materials mainly contain topological insulator,topological metal/semimetal and topological superconductor.In the study of topological materials,ARPES plays an important rule.In this paper,I firstly introduce the basic principle and system components of ARPES.Then I will show the experimental research results about ARPES study of serious topological materials.By systematic study,we found the topological entangled Rashba-split bands on the grey arsenic,we observed strong evidence for topological bulk energy gap and edge states in the top surface and steps edges of ZrTe5 respectively,we firstly discovered hourglass fermion in nonsymmorphic TI KHgSb,what's more,we also discovered the triple point with surface states in single crystal WC,and so on.Our studies provide first-hand data for searching the new fermions in solid states,and promote the future study in this field.