# Linear behavior of the optical conductivity and incoherent charge transport in ${\mathrm{BaCoS}}_{2}$

• Santos-Cottin, D. LPEM, ESPCI Paris, PSL University
• Klein, Y. Institut de Minéralogie de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, Paris, France
• Werner, Philipp Department of Physics, University of Fribourg, Switzerland
01.10.2018
Published in:
• Physical Review Materials. - 2018, vol. 2, no. 10, p. 105001
English Optical conductivity measurements on a BaCoS2 single crystal unveil an unusual linear behavior over a broad spectral range. In the paramagnetic phase above 300 K, the spectrum shows no gap, which contradicts the previously proposed scenario of a charge-transfer Mott insulator. Ab initio dynamical mean field theory calculations including a retarded Hubbard interaction explain the data in terms of an incipient opening of a Co(3d)−S(3p) charge-transfer gap concomitant to incoherent charge transport driven by electronic correlations. These results point to a non-Fermi liquid scenario with Hund's metal properties in the paramagnetic state, which arises from an incipient Mott phase destabilized by low-energy charge fluctuations across the vanishing 3d−3p charge-transfer gap.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
• English
Classification
Physics