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, that is consistent with a spin-selective bottleneck effect due to the presence of spin polarized cone-like 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.
@article{arxiv.1912.06572,
title = {Spin-, time- and angle-resolved photoemission spectroscopy on WTe$_2$},
author = {Mauro Fanciulli and Jakub Schusser and Min-I Lee and Zakariae El Youbi and Olivier Heckmann and Maria Christine Richter and Cephise Cacho and Carlo Spezzani and David Bresteau and Jean-François Hergott and Pascal D'Oliveira and Olivier Tcherbakoff and Thierry Ruchon and Jan Minár and Karol Hricovini},
journal= {arXiv preprint arXiv:1912.06572},
year = {2020}
}