Abstract
Topological semimetals are gapless states of matter which have robust surface states and characteristic electromagnetic responses. In this paper, we consider the electromagnetic response of gapless phases in dimensions with line nodes. We show through a layering approach that an intrinsic antisymmetric tensor (2-form), which is determined by the geometry and energy-embedding of the nodal lines, emerges in the effective response field theory. is shown to be simply related to the charge polarization and orbital magnetization of the sample; hence the geometry of the line nodes determines these electromagnetic observables. We conclude by discussing the relevance for recently proposed materials and heterostructures with line-node fermi-surfaces.
- Received 14 March 2016
- Revised 22 December 2016
DOI:https://doi.org/10.1103/PhysRevB.95.075138
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