Topological nodal semimetals

@article{Burkov2011TopologicalNS,
  title={Topological nodal semimetals},
  author={Anton A. Burkov and Michael David Hook and Leon Balents},
  journal={Physical Review B},
  year={2011},
  volume={84},
  pages={235126}
}
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… 

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