Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 12: Correlated Electrons: Materials
TT 12.13: Vortrag
Dienstag, 6. September 2022, 12:45–13:00, H22
Tuning the multiorbital Mott transition of BaCoS2 — •Haneen Abushammala1,2, Yannick Klein1, and Andrea Gauzzi1 — 1IMPMC, Sorbonne University, 4, place Jussieu, 75005 Paris, France — 2Institute for Experimental Physics IV, Ruhr-Universität Bochum, Germany
The quasi-2D BaCoS2 system displays an unusual Mott state concomitant with a stipe-type antiferromagnetic (AFM) ordering at TN=305 K in a square-lattice of Co2+. Electron doping by partial Co/Ni substitution, or hydrostatic pressure drives the system into a paramagnetic and Fermi Liquid (FL) metallic phase. Interestingly, this metal-insulator transition (MIT) is not accompanied by any significant structural distortion, which offers ideal conditions to investigate the FL to non-FL crossover in a model square-lattice system in the regime of moderate electronic correlations typical of sulphides. In order to investigate the interplay between AFM order and Mott state, we have studied the effect of chemical pressure and hole doping on the AFM order by partially substituting Sr and K for Ba respectively. Contrary to the case of hydrostatic pressure, we find that chemical pressure significantly reduces TN down to 240 K for a substitution level of 8 at%, corresponding to an effective pressure of 0.3 GPa. The K-substitution is found to induce similar suppression of the AFM order as compared to the Sr-substitution. However, its sizable value of Sommerfeld coefficient (5.7 mJ/mol.K2) suggests a metallic state induced by hole doping. Studies on single crystals may unveil whether the metallic state induced by K-doping displays FL-properties.