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arXiv · 1912.06572

Spin-, time- and angle-resolved photoemission spectroscopy on WTe$_2$

Mauro Fanciulli·Jakub Schusser·Min-I Lee·Zakariae El Youbi·Olivier Heckmann·Maria Christine Richter·Cephise Cacho·Carlo Spezzani·David Bresteau·Jean-François Hergott·Pascal D'Oliveira·Olivier Tcherbakoff·Thierry Ruchon·Jan Minár·Karol Hricovini
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Abstract

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 WTe$_2$, 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 WTe$_2$ 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.

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Mauro Fanciulli, Jakub Schusser, Min-I Lee, Zakariae El Youbi, Olivier Heckmann, Maria Christine Richter, Cephise Cacho, Carlo Spezzani, David Bresteau, Jean-François Hergott, Pascal D'Oliveira, Olivier Tcherbakoff, Thierry Ruchon, Jan Minár, Karol Hricovini. 2019-12-13. Spin-, time- and angle-resolved photoemission spectroscopy on WTe$_2$. https://doi.org/10.1103/physrevresearch.2.013261

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