Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 56: Poster Session: Low-Dimensional Systems

TT 56.17: Poster

Mittwoch, 22. März 2017, 15:00–19:00, P2-OG4

Transport and thermodynamic studies of the metal-insulator transition in κ-(BEDT-TTF)₂Hg(SCN)₂Cl under He-gas pressure — •Caroline Delleske¹, David Zielke¹, Elena Gati¹, Harald Schubert¹, John A. Schlueter², and Michael Lang¹ — ¹Physikalisches Institut, SFB/TR49, Goethe Uni Frankfurt, DE — ²Materials Science Division, NSF, Arlington, Virginia, USA

Organic charge-transfer salts show a wide variety of electronic phases resulting from strong electron correlations in low dimensions, such as superconductivity or multiferroicity. The members of the κ-(BEDT-TTF)₂X family are representing model systems to investigate the interplay of strong on-site and inter-site Coulomb repulsion in 2D. Here we focus on the less intensively studied system κ-(BEDT-TTF)₂Hg(SCN)₂Cl [1, 2], showing a metal-insulator (MI) transition at T_MI ≈ 30 K which has been assigned to charge-order [1]. We report on a detailed characterization of the material’s low-temperature properties by transport and thermodynamic measurements at ambient pressure, as well as under finite He-gas pressure. We find a slightly broadened MI transition, consistent with literature [2], which can be rapidly suppressed with increasing pressure. Surprisingly, no indications for superconductivity can be found up to pressures of p = 300 MPa and temperatures down to T = 2.4 K. In addition, we will present thermodynamic studies of the specific heat and thermal expansion to unravel the role of spin and lattice degrees of freedom at T_MI.

[1] N. Drichko et al., PRB 89, 075133 (14)

[2] S. Yasin et al., Physica B 407, 1689 (12)