Valence band momentum imaging of NiTe2 by two-photon photoemission momentum microscopy

Two-photon photoemission (2PPE) spectroscopy on NiTe2 is performed by the combination of femtosecond ultraviolet laser pulses with the time-of-flight photoelectron momentum microscopy. At the photon energies of 2.9 and 3.1 eV, the bulk Te 5pz valence bands as well as the spin-orbit split Te 5px,y valence bands are identified. Detailed momentum patterns of the Te 5px,y bands are revealed, and the size of their splitting is estimated as 0.5+0.2−0.1 eV. Our 2PPE experiments on NiTe2 would open up the opportunities for future time-resolved studies of its unoccupied electronic states.