Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 37: Topological Semimetals - Theory (joint session TT/MA)
TT 37.8: Talk
Wednesday, April 3, 2019, 11:30–11:45, H22
Disorder-driven exceptional lines and Fermi ribbons in tilted nodal-line semimetals — •Kristof Moors1, Alexander A. Zyuzin2, 3, Alexander Yu. Zyuzin3, Rakesh P. Tiwari4, and Thomas L. Schmidt1 — 1University of Luxembourg, Luxembourg, Luxembourg — 2Aalto University, Aalto, Finland — 3Ioffe Physical-Technical Institute, St. Petersburg, Russia — 4McGill University, Montréal, Québec
We consider the impact of disorder on the spectrum of three-dimensional nodal-line semimetals. We show that the combination of disorder and a tilted spectrum naturally leads to a non-Hermitian self-energy contribution that can split a nodal line into a pair of exceptional lines. These exceptional lines form the boundary of an open and orientable bulk Fermi ribbon in reciprocal space on which the energy gap vanishes. We find that the surface of such a disorder-induced bulk Fermi ribbon in general lies orthogonal to the direction of the tilt, which can be exploited to realize a bulk Fermi ribbon with nontrivial topology by means of a tilt vector that twists along a nodal loop. Our results put forward a new paradigm for the exploration of non-Hermitian topological phases of matter.