Fig. 3: Observation of fourfold VHSs in TaCo2Te2 and predicted realization of hourglass fermions in TaIr2Te2.
From: Realization of practical eightfold fermions and fourfold van Hove singularity in TaCo2Te2
a DFT calculated fourfold bands along \({\rm{S}}-{\rm{Z}}-{\rm{T}}\). b, d Fermi surface in \({k}_{x}-{k}_{y}\) plane measured with photon energy \(90{eV}\), with the measurement plane defined by the incident light and emitted electrons parallel to \({\rm{Z}}-{\rm{S}}\) (b) and \({\rm{Z}}-{\rm{T}}\) (d) directions, respectively. c, e Second derivative ARPES spectra taken from the momentum cut indicated by red lines in (b) and (d), respectively. f Second derivative ARPES spectra showing the feature of hourglass fermion predicted in TaCo2Te2. g–i DFT predicted hourglass fermions.
