Discovery of a ThreeDimensional Topological Dirac Semimetal, Na_{3}Bi
Abstract
Threedimensional (3D) topological Dirac semimetals (TDSs) represent an unusual state of quantum matter that can be viewed as “3D graphene.” In contrast to 2D Dirac fermions in graphene or on the surface of 3D topological insulators, TDSs possess 3D Dirac fermions in the bulk. By investigating the electronic structure of Na_{3}Bi with angleresolved photoemission spectroscopy, we detected 3D Dirac fermions with linear dispersions along all momentum directions. Furthermore, we demonstrated the robustness of 3D Dirac fermions in Na_{3}Bi against in situ surface doping. Our results establish Na_{3}Bi as a model system for 3D TDSs, which can serve as an ideal platform for the systematic study of quantum phase transitions between rich topological quantum states.
 Publication:

Science
 Pub Date:
 February 2014
 DOI:
 10.1126/science.1245085
 arXiv:
 arXiv:1310.0391
 Bibcode:
 2014Sci...343..864L
 Keywords:

 PHYSICS Physics, AppliedPhysics, MaterialsScience;
 Condensed Matter  Materials Science;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Other Condensed Matter
 EPrint:
 4 figures in main text