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arXiv · 1807.05664

Evidence for breathing-type pseudo Jahn-Teller distortions in the charge density wave phase of 1$T$-TiSe$_2$

A. Wegner·J. Zhao·J. Li·J. Yang·A. A. Anikin·G. Karapetrov·D. Louca·U. Chatterjee
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Abstract

The charge density wave (CDW) phase in 1$T$-TiSe$_2$ is investigated using angle resolved photoemission spectroscopy (ARPES) and neutron scattering measurements. Our ARPES results reveal a clear temperature dependence of the chemical potential of the system. They also demonstrate specific changes encountered by the Se 4$p$ valence and Ti 3$d$ conduction bands as the temperature of the system is decreased through $T_{\text{CDW}}$. The valence band undergoes a downward shift, whereas the conduction band remains unaffected. The crystal structure in the CDW state shows a distinct split of the Ti-Se atomic correlations that are reminiscent of Jahn-Teller distortions, manifested in a breathing-type mode. The ARPES data together with the local structure analysis support a direct link between Jahn-Teller-like distortions and the CDW order in 1$T$-TiSe$_2$.

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A. Wegner, J. Zhao, J. Li, J. Yang, A. A. Anikin, G. Karapetrov, D. Louca, U. Chatterjee. 2018-07-16. Evidence for breathing-type pseudo Jahn-Teller distortions in the charge density wave phase of 1$T$-TiSe$_2$. https://arxiv.org/abs/1807.05664

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