Topological nodal semimetals

By A. Burkov, M. Hook, L. Balents. 2011

1,133 citations recorded by the source corpus.

We present a study of “nodal-semimetal” phases in which nondegenerate conduction and valence bands touch at points (the “Weyl semimetal”) or lines (the “line-node semimetal”) in three-dimensional momentum space. We discuss a general approach to such states by perturbation of the critical point between a normal insulator (NI) and a topological insulator (TI), breaking either time-reversal (TR) or inversion symmetry. We give an explicit model realization of both types of states in a NI-TI superlattice structure with broken TR symmetry. Both the Weyl and the line-node semimetals are characterized by topologically protected surface states, although in the line-node case, some additional symmetries must be imposed to retain this topological protection. The edge states have the form of “Fermi arcs” in the case of the Weyl semimetal: these are chiral gapless edge states, which exist in a finite region in momentum space, determined by the momentum-space separation of the bulk Weyl nodes. The chiral character of the edge states leads to a finite Hall conductivity. In contrast, the edge states of the line-node semimetal are “flat bands”: these states are approximately dispersionless in a subset of the two-dimensional edge Brillouin zone, given by the projection of the line node onto the plane of the edge. We discuss unusual transport properties of the nodal semimetals and, in particular, point out quantum critical-like scaling of the dc and optical conductivities of the Weyl semimetal and similarities to the conductivity of graphene in the line-node case.

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

View Paper: https://www.semanticscholar.org/paper/3d401b640e1341ff8e227b7467b42d43e9d92dda

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. Ashvin Vishwanath
2. N. P. Armitage
3. E. Mele
4. Ling Lu
5. X. Dai
6. Z. Fang
7. H. Weng
8. Xiao-Liang Qi

In Materials Chemistry

1. Ashvin Vishwanath
2. N. P. Armitage
3. E. Mele
4. Xiao-Liang Qi
5. Z. Fang
6. X. Dai
7. H. Weng
8. J. Venderbos

Citations in the corpus

• Inhomogeneous Weyl and Dirac Semimetals: Transport in Axial Magnetic Fields and Fermi Arc Surface States from Pseudo-Landau Levels (2016, background): “The first term encodes the conductivity due to a finite Fermi surface [103, 104].”
• Topological photonics (2018, neutral): “Phys., Vol. 91, No. 1, January–March 2019 015006-47 nodal rings (Burkov, Hook, and Balents, 2011), nodal chains (Bzdusek et al., 2016), nodal links (Yan et al., 2017), and nodal knots (Bi et al., 2017a).”
• Topological node-line semimetal in three-dimensional graphene networks (2014, background): “Different from other proposals for the topological node-lines, [21] the appearance of node-lines in MTC is very stable and does not require fine tuning of any parameters.”