Spin, time, and angle resolved photoemission spectroscopy on WTe2

Mauro Fanciulli (1, 2) , Jakub Schusser (1, 3, 2) , Min-I Lee (1, 2) , Zakariae El Youbi (1, 4, 2) , Olivier Heckmann (1, 2) , Maria Christine Richter (1, 2) , Cephise Cacho (4) , Carlo Spezzani (5) , David Bresteau (2, 6) , Jean-François Hergott (2, 6) , Pascal d'Oliveira (2, 7) , Olivier Tcherbakoff (2, 7) , Thierry Ruchon (2, 6) , Ján Minár (3) , Karol Hricovini (1, 2)

1 LPMS - Laboratoire de Physique des Matériaux et des Surfaces
2 LIDYL - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)
3 University of West Bohemia [Plzeň ]
4 DIAMOND Light source
5 Elettra Sincrotrone Trieste
6 ATTO - Attophysique
7 SLIC - Serveurs Laser

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.

Domaines: Physique [physics]

Mauro Fanciulli, Jakub Schusser, Min-I Lee, Zakariae El Youbi, Olivier Heckmann, et al.. Spin, time, and angle resolved photoemission spectroscopy on WTe2. Physical Review Research, 2020, 2 (1), ⟨10.1103/PhysRevResearch.2.013261⟩. ⟨hal-02908130⟩