Event Details

Topological ideas have revitalized the study of gapped insulating phases of matter. My talk will examine the role of such ideas in understanding semimetals, gapless phases whose Fermi surfaces may be shrunk to isolated point or line nodes. First, I will review the theory of ‘Weyl semimetals' that arise from accidental degeneracies in 3D crystals, and explore the consequences of the resulting band topology. Then, I will show that the interplay of crystal symmetry and topology can aid in identifying “filling enforced” semimetals. I will discuss how the topological underpinnings of these gapless phases may be probed via transport or spectroscopy. Finally, if time permits, I will sketch ongoing work in using these ideas to identify novel phases in heavy fermion systems.

References:
arXiv:1508.01546; Nat. Phys. 9, 299 (2013); PRX 4, 031035; PRX 5, 041046;

Related work:
arXiv:1609.04023