Dresden 2026 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 92: Post-Deadline Session
O 92.1: Vortrag
Donnerstag, 12. März 2026, 19:30–19:45, HSZ/AUDI
Surface superconductivity in Weyl semimetals — •Francesco Buccheri1, Alessandro De Martino2, Rafael Fernandes3, and Jeroen van den Brink1 — 1IFW Dresden, DE — 2City St George's, University of London, UK — 3University of Illinois Urbana-Champaign, US
It was recently observed experimentally that the topological surface states of Weyl semimetals, known as Fermi arcs, may develop a superconducting gap, while bulk superconductivity remains absent. What drives the formation of this novel superconducting state is an open question. Here we show that surface superconductivity in time-reversal-invariant Weyl semimetals may arise from the interaction of Fermi arc electrons with both surface and bulk phonons. Employing a low-energy Hamiltonian including Coulomb repulsion and electron-phonon interactions, we derive the effective theory on the Fermi arcs. We find that the combined effect of the Fermi arcs being disconnected and weak screening of the Coulomb repulsion at the system's surface causes nodes to appear in the superconducting gap, in accordance with recent photoelectron spectroscopy experiments on PtBi2. This suggests that engineering the Coulomb screening, e.g. by a surface layer coating, may strongly affect the critical temperature, as well as size and even symmetry of the surface superconducting gap.
Keywords: Weyl semimetals; topological states of matter; superconductivity; electron-phonon interaction; PtBi2