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arXiv · 1103.2104

Many-body effects in TiSe2: Can GW describe an Excitonic Insulator?

M. Cazzaniga·H. Cercellier·M. Holzmann·C. Monney·P. Aebi·G. Onida·V. Olevano
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Abstract

We present both theoretical ab initio GW and experimental angle-resolved photoemission (ARPES) and scanning tunneling (STS) spectroscopy results on TiSe2. With respect to the density-functional Kohn-Sham metallic picture, the many-body GW self-energy leads to a ~ 0.2 eV band gap insulator consistent with our STS spectra at 5 K. The band shape is strongly renormalized, with the top-of-valence moved towards a circle of points away from Γ, arising in a mexican hat feature typical of an excitonic insulator. Our calculations are in good agreement with experiment.

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M. Cazzaniga, H. Cercellier, M. Holzmann, C. Monney, P. Aebi, G. Onida, V. Olevano. 2011-07-12. Many-body effects in TiSe2: Can GW describe an Excitonic Insulator?. https://arxiv.org/abs/1103.2104

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