Discovery of a Three-Dimensional Topological Dirac Semimetal, Na3Bi

By Zhongkai Liu, Bo Zhou, Y. Zhang, Zhi-jie Wang, H. Weng, D. Prabhakaran, S. Mo, Zhi-xun Shen, Z. Fang, X. Dai and 2 more. Science, 2013

1,928 citations recorded by the source corpus.

A 3D Graphene? Discoveries of materials with exciting electronic properties have propelled condensed matter physics over the past decade. Two of the best-known examples, graphene and topological insulators, have something in common: a linear energy-momentum relationship—the Dirac dispersion—in their two-dimensional (2D) electronic states. Topological insulators also have a more mundane aspect of their electronic structure, characterized by a band gap. Another class of materials, topological Dirac semimetals, has been proposed that has a linear dispersion along all three momentum directions—a bulk Dirac cone; these materials are predicted to have intriguing electronic properties and to be related to other exotic states through quantum phase transitions. Liu et al. (p. 864, published online 16 January) detected such a state in the compound Na3Bi by using photoemission spectroscopy. Angle-resolved photoemission spectroscopy is used to detect bulk Dirac cones in a three-dimensional analog of graphene. Three-dimensional (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 Na3Bi with angle-resolved photoemission spectroscopy, we detected 3D Dirac fermions with linear dispersions along all momentum directions. Furthermore, we demonstrated the robustness of 3D Dirac fermions in Na3Bi against in situ surface doping. Our results establish Na3Bi 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.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/3a02f2e920611f484f83ab5458e2181f315029bc

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Citations in the corpus

Topological Semimetals from First Principles (2018, background): “Following the first-principles predictions of the Dirac semimetals in Na3Bi and Cd3As2, angle-resolved photoemission spectroscopy experiments have confirmed the existence of Dirac points in these two materials (67, 68), making them the primary object of experimental studies addressing the special el”
Anisotropic Fermi Surface and Quantum Limit Transport in High Mobility Three-Dimensional Dirac Semimetal Cd 3 As 2 (2014, background): “onal (3D) topological Dirac semimetal, a new type of topological materials with a pair of nondegenerate 3D massless Weyl fermions becomes a rapid growing field of research in condensed matter physics [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]. In analogy to two dimensional Dirac points observed in ”
Angle-resolved photoemission studies of quantum materials (2020, neutral): “Dirac semimetals were first observed by ARPES in Na3Bi (Liu et al., 2014d) and Cd3As2 (Borisenko et al., 2014; Liu et al., 2014c; Neupane et al., 2014), with the salient features summarized in Fig.”
Observation of a three-dimensional topological Dirac semimetal phase in high-mobility Cd3As2 (2013, background): “Later, two other preprints (refs [42] and [43]) report experimental realization of the 3D Dirac phase in a metastable low mobility compound, Na3Bi.”
Nodal-link semimetals (2017, background): “[16] ZK Liu, B Zhou, Y Zhang, ZJ Wang, HM Weng, D Prabhakaran, S-K Mo, ZX Shen, Z Fang, X Dai, et al.”
Experimental observation of Weyl points (2015, background): “[24] ZK Liu, B Zhou, Y Zhang, ZJ Wang, HM Weng, D Prabhakaran, S-K Mo, ZX Shen, Z Fang, X Dai, et al.”