Quantization of the band at the surface of charge density wave material 2H-TaSe2 *

By using angle-resolved photoemission spectroscopy (ARPES) combined with the first-principles electronic structure calculations, we report quantized states at surface of a single crystal 2H-TaSe2. We have observed sub-bands three-dimensional Brillouin zone center due to highly dispersive band light effective mass along kz direction. The shift upward towards EF while bulk Γ shifts downward decrease temperature across charge density wave (CDW) formation. could be intimately related CDW. While neither two-dimensional Fermi-surface nesting nor purely strong electron–phonon coupling can explain mechanism CDW in 2H-TaSe2, our experiment may ignite interest understanding this family.