SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 30: 2D Materials I: Electronic Structure
O 30.1: Vortrag
Dienstag, 28. März 2023, 10:30–10:45, GER 37
Controlling the charge density wave transition in single-layer TiTe2xSe2(1−x) alloys by band gap engineering — •Tommaso Antonelli, Andela Zivanovic, Chiara Bigi, Brendan Edwards, Akhil Rajan, and Phil King — University of St. Andrews
The narrow gap semiconductor monolayer (ML) TiSe2 undergoes a controversial charge density wave transition [1, 2] whose nature is still poorly understood. Recently, a similar instability has been observed in the sister semimetallic compound ML-TiTe2 showing a weaker CDW coupling as compared to the selenide compound [3, 4]. Using molecular beam epitaxy, we grow ML-TiTe2xSe2(1−x) alloys to engineer the band gap in the normal phase and tune the CDW coupling in the system. Performing angle-resolved photoemission spectroscopy on the alloy films, we demonstrate the effective semiconductor to semimetal transition in the high-temperature phase band structure and observe the consequent modulation of the CDW critical temperature. Our experimental results are rationalised using a simple theoretical model bringing new insight on how to manipulate this collective phase at the 2D limit.
[1] P. Chen et al., Nat. Commun. 6, 8943 (2015) [2] M. D. Watson et al., 2D Materials 8, 015004, (2021) [3] P. Chen et al., Nat. Commun., 8, 516 (2017) [4] T. Antonelli et al., npj Quantum Mater. 7, 98 (2022)