Spin, time, and angle resolved photoemission spectroscopy on WTe2
Résumé
We combined a spin resolved photoemission spectrometer with a high-harmonic generation (HHG) laser
source in order to perform spin, time, and angle resolved photoemission spectroscopy (STARPES) experiments
on the transition metal dichalcogenide bulk WTe2, a possible Weyl type-II semimetal. Measurements at different
femtosecond pump-probe delays and comparison with spin resolved one-step photoemission calculations provide
insight into the spin polarization of electrons above the Fermi level in the region where Weyl points of WTe2 are
expected. We observe a spin accumulation above the Weyl points region, which is consistent with a spin-selective
bottleneck effect due to the presence of spin-polarized conelike electronic structure. Our results support the
feasibility of STARPES with HHG, which despite being experimentally challenging provides a unique way to
study spin dynamics in photoemission.