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arXiv · 2406.10550

Ultrafast carrier dynamics throughout the three-dimensional Brillouin zone of the Weyl semimetal PtBi$_2$

Paulina Majchrzak·Charlotte Sanders·Yu Zhang·Andrii Kuibarov·Oleksandr Suvorov·Emma Springate·Iryna Kovalchuk·Saicharan Aswartham·Grigory Shipunov·Bernd Büchner·Alexander Yaresko·Sergey Borisenko·Philip Hofmann
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Abstract

Using time- and angle-resolved photoemission spectroscopy, we examine the unoccupied electronic structure and electron dynamics of the type-I Weyl semimetal PtBi$_2$. Using the ability to change the probe photon energy over a wide range, we identify the predicted Weyl points in the unoccupied three-dimensional band structure and we discuss the effect of $k_\perp$ broadening in the normally unoccupied states. We characterise the electron dynamics close to the Weyl point and in other parts of three-dimensional Brillouin zone using $k$-means, an unsupervised machine learning technique. This reveals distinct differences -- in particular, dynamics that are faster in the parts of the Brillouin zone that host most of the bulk Fermi surface than in parts close to the Weyl points.

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Paulina Majchrzak, Charlotte Sanders, Yu Zhang, Andrii Kuibarov, Oleksandr Suvorov, Emma Springate, Iryna Kovalchuk, Saicharan Aswartham, Grigory Shipunov, Bernd Büchner, Alexander Yaresko, Sergey Borisenko, Philip Hofmann. 2024-06-15. Ultrafast carrier dynamics throughout the three-dimensional Brillouin zone of the Weyl semimetal PtBi$_2$. https://doi.org/10.1103/physrevresearch.7.013025

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