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TT: Fachverband Tiefe Temperaturen

TT 27: Correlated Electrons: Other Materials

TT 27.8: Talk

Tuesday, March 19, 2024, 11:30–11:45, H 3010

Influence of chemical/structural modifications in layered organic salts κ-(BEDT-TTF)₂X near the Mott transition probed by magnetic quantum oscillations. — •Shamil Erkenov^1,2, Florian Kollmannsberger^1,2, Werner Biberacher¹, Ilya Sheikin³, Toni Helm⁴, Natalia Kushch¹, Rudolf Gross^1,2, and Mark Kartsovnik¹ — ¹Walther-Meißner-Institut, Garching, Germany — ²Technische Universität München, Garching, Germany — ³Laboratoire National des Champs Magnétiques Intenses, Grenoble, France — ⁴Hochfeld-Magnetlabor Dresden, HZDR, Dresden, Germany

One of the prominent systems for studying Mott metal-insulating transition (MIT) are organic salts κ-(BEDT-TTF)₂X. These salts have different electronic ground states, determined by electronic corelations U/t and spin frustration ratio t^′/t, which can be tuned by a pressure or via chemical/structural modifications, such as anion substitution or ordering of the BEDT-TTF ethylene endgroups. It was believed that chemical/structural modifications act similarly to physical pressure and change electronic state of the system via changing U/t. However, first-principles band-structure calculations [1] suggest that anion substitution in κ salts influences the ground state primarily through the change of the ratio t^′/t rather than U/t. Here we report on comparative studies of magnetic quantum oscillations in the κ salts, with X = Cu(NCS)₂, Cu[N(CN)₂]Y (Y=Cl, Br) and Cu₂(CN)₃ to trace the correlations between the anion substitution and the mentioned ratios. [1] T. Koretsune and C. Hotta, Phys. Rev. B 89, 045102 (2014).

Keywords: Mott transition; Magnetic quantum oscillations; Organic superconductors