A stable three-dimensional topological Dirac semimetal Cd3As2

• Published in: Nature materials Vol. 13; no. 7; pp. 677 - 681
• Main Authors: Liu, Z. K., Jiang, J., Zhou, B., Wang, Z. J., Zhang, Y., Weng, H. M., Prabhakaran, D., Mo, S-K., Peng, H., Dudin, P., Kim, T., Hoesch, M., Fang, Z., Dai, X., Shen, Z. X., Feng, D. L., Hussain, Z., Chen, Y. L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-07-2014; Nature Publishing Group
• Subjects: 140/146; 639/301/1005/1007; 639/301/119/995; 639/766/119/2792; Biomaterials; Carbon; Condensed Matter Physics; letter; Materials Science; Matter & antimatter; Metals; Nanotechnology; Optical and Electronic Materials; Physics; Quantum physics; Spectroscopy; Three dimensional imaging; Topology
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat3990

A state of matter known as a three-dimensional Dirac semimetal has latterly garnered significant theoretical and experimental attention. Using angle-resolved photoelectron spectroscopy, it is shown that Cd
3
As
2
is an experimental realization of a three-dimensional Dirac semimetal that is stable at ambient conditions.
Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter
1
,
2
,
3
,
4
,
5
,
6
that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals
1
,
7
, axion insulators
1
,
4
and topological superconductors
8
,
9
), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd
3
As
2
, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, β-cristobalite BiO
2
(ref. 
3
) and Na
3
Bi (refs 
4
,
5
), Cd
3
As
2
is stable and has much higher Fermi velocities. Furthermore, by
in situ
doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.