Regensburg 2019 – scientific programme

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O: Fachverband Oberflächenphysik

O 85: Ultrafast Electron Dynamics at Surfaces and Interfaces II: New Methods and Developments

O 85.9: Talk

Thursday, April 4, 2019, 17:00–17:15, H16

Time- and angle-resolved photoelectron spectroscopy of the three-dimensional Dirac semimetal Cd₃As₂ — •Hermann Erk¹, Petra Hein¹, Stephan Jauernik¹, Lexian Yang², Yulin Chen³, Zhongkai Liu⁴, Dharmalingam Prabhakaran³, and Michael Bauer¹ — ¹IEAP, CAU Kiel, Germany — ²Physics Department, Tsinghua University, Beijing, China — ³Physics Department, Oxford University, United Kingdom — ⁴School of Physical Science and Technology, ShanghaiTech University, China

Dirac semimetals exhibit a characteristic linear band dispersion in the vicinity of discrete points in momentum space. The most prominent examples are 2D Dirac cones in graphene and at the surfaces of topological insulators. However, cone-shaped band dispersions were proposed to exist also in 3D [1]. A material that was experimentally verified to host a pair of 3D Dirac cones is Cd₃As₂ [2].

Here, we present first results of a time- and angle-resolved photoemission study of the (112) surface of Cd₃As₂. While the band dispersion of the Dirac cone has already been subject of several studies, only little is known about the ultrafast carrier dynamics in this material. Our technique enables us to get the first momentum-resolved insights into the dynamics in the vicinity of the 3D Dirac cone initiated by the absorption of 840 nm pump pulses. The results are discussed under consideration of recent studies of Cd₃As₂ and in comparison to ultrafast dynamics observed in related materials.

[1] S. M. Young, S. Zaheer et al., Phys. Rev. Lett. 108, 140405 (2012).

[2] M. Neupane, S.-Y. Xu et al., Nat. Commun. 5, 3786 (2014).