Triple point fermions in ferroelectric GeTe

Abstract

Ferroelectric GeTe is unveiled to exhibit an intriguing multiple non-trivial topology of the electronic band structure due to the existence of triple-point and type-II Weyl fermions, which goes well beyond the giant Rashba spin splitting controlled by external fields as previously reported. Using spin- and angle-resolved photoemission spectroscopy combined with ab initio density functional theory, the unique spin texture around the triple point caused by the crossing of one spin degenerate and two spin-split bands along the ferroelectric crystal axis is derived. This consistently reveals spin winding numbers that are coupled with time reversal symmetry and Lorentz invariance, which are found to be equal for both triple-point pairs in the Brillouin zone. The rich manifold of effects opens up promising perspectives for studying non-trivial phenomena and multi-component fermions in condensed matter systems.

arXiv comment5 pages, 5 figures

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Cited by in corpus (9)

• Gate-dependent non-linear Hall effect at room temperature in topological semimetal GeTe
• Triple nodal points characterized by their nodal-line structure in all magnetic space groups
• Field-induced ultrafast modulation of Rashba coupling at room temperature in ferroelectric $\alpha$-GeTe(111)
• Superconducting properties of the spin Hall candidate Ta3Sb with eightfold degeneracy
• Reentrant proximity-induced superconductivity for GeTe semimetal
• Punctured-Chern topological invariants for semi-metallic bandstructures
• Spin-valve effect for spin-polarized surface states in topological semimetals
• Conduction Band Structure and Ultrafast Dynamics of Ferroelectric $\alpha$-GeTe(111)
• Surface spin polarization in the magnetic response of GeTe Rashba ferroelectric