Selective observation of surface and bulk bands in polar WTe2 by laser-based spin- and angle-resolved photoemission spectroscopy

Abstract

The electronic state of ${\mathrm{WTe}}_{2}$, a candidate of type-II Weyl semimetal, is investigated by using laser-based spin- and angle-resolved photoemission spectroscopy. We prepare the pair of ${\mathrm{WTe}}_{2}$ samples, one with a (001) surface and the other with a ($00\overline{1}$) surface, by the ``sandwich'' method'', and we measure the band structures of each surface separately. The Fermi arcs are observed on both surfaces. We identify that the Fermi arcs on the two surfaces both originate from surface states. We further find a surface resonance band, which connects with the Fermi-arc band, forming a Dirac-cone-like band dispersion. Our results indicate that the bulk electron and hole bands are much closer in momentum space than band calculations.