SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 34: Ultrafast Electron Dynamics at Surface and Interfaces III
O 34.9: Vortrag
Dienstag, 28. März 2023, 12:45–13:00, TRE Phy
Ultrafast charge separation and charge density wave suppression in monolayer TiSe2 on graphite — •Sebastian Buchberger1,2, Charlotte Sanders3, Yu Zhang3, Emma Springate3, Paulina Majchrzak4, Jill Miwa4, Philip Hofmann4, Søren Ulstrup4, and Phil D. C. King1 — 1University of St Andrews, UK — 2MPI for Chemical Physics of Solids, Dresden, Germany — 3Central Laser Facility, UK — 4Aarhus University, Denmark
The properties of two-dimensional materials and their heterostructures are often governed by the interplay of several coexisting interactions which can be difficult to disentangle in equilibrium. Time and angle resolved photoelectron spectroscopy (trARPES) is emerging as a powerful method to investigate such systems, allowing the observation of ultrafast processes such as the buildup of charge screening1, optically induced bandgap renormalisation2 and interlayer charge separation3. Here we present a trARPES study on monolayer TiSe2 grown epitaxially on graphite. Monolayer TiSe2 is a small indirect bandgap semiconductor that exhibits an unconventional charge density wave (CDW) in its ground state, whose origin and nature are still not fully established4. We study how the electronic structure evolves upon photoexcitation, tracking band shifts and spectral weight variations to disentangle charge separation, screening, and dynamical suppression of the CDW.
1T. Rohwer et al., Nature 471, 490-493 (2011), 2S. Ulstrup et al., ACS Nano 10, 6315-6322 (2016), 3S. Aeschlimann, Sci. Adv. 6, eaay0761 (2020), 4P. Chen et al., Nat. Commun. 6:8943 (2015)