Anisotropic charge dynamics in the quantum spin-liquid candidate κ−(BEDT-TTF)2Cu2(CN)3

Scientific paper - Original scientific paper

• Author: Marija Pinterić
• Author: M. Čulo
• Author: Ognjen Milat
• Author: Mario Basletić
• Author: Bojana Korin-Hamzić
• Author: Emil Tafra
• Author: Amir Hamzić
• Author: T. Ivek
• Author: T. Peterseim
• Author: K. Miyagawa
• Author: K. Kanoda
• Author: J. A. Schlueter
• Author: M. Dressel
• Author: S. Tomić
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

We have in detail characterized the anisotropic charge response of the dimer Mott insulator κ−(BEDT-TTF)2Cu2(CN)3 by dc conductivity, Hall effect, and dielectric spectroscopy. At room temperature, the Hall coefficient is positive and close to the value expected from stoichiometry; the temperature behavior follows the dc resistivity ρ(T). Within the planes the dc conductivity is well described by variable-range hopping in two dimensions; this model, however, fails for the out-of-plane direction. An unusually broad in-plane dielectric relaxation is detected below about 60 K; it slows down much faster than the dc conductivity following an Arrhenius law. At around 17 K, we can identify a pronounced dielectric anomaly concomitantly with anomalous features in the mean relaxation time and spectral broadening. The out-of-plane relaxation, on the other hand, shows a much weaker dielectric anomaly; it closely follows the temperature behavior of the respective dc resistivity. At lower temperatures, the dielectric constant becomes smaller both within and perpendicular to the planes; also, the relaxation levels off. The observed behavior bears features of relaxorlike ferroelectricity. Because heterogeneities impede its long-range development, only a weak-tunneling-like dynamics persists at low temperatures. We suggest that the random potential and domain structure gradually emerge due to the coupling to the anion network.

• Keywords (english): strongly correlated systems; two-dimensional molecular solids; dielectric response; Hall effect; Mott insulators; quantum spin liquid
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical review B: Condensed matter and materials physics
• Numbering: vol. 90, no. 9, 195139
• p-ISSN: 1098-0121
• e-ISSN: 1550-235X
• DOI: https://doi.org/10.1103/PhysRevB.90.195139
• URN:NBN: urn:nbn:hr:217:944838
• Publication: 2014
• Project: Number: IP-2013-11-1011; Title (croatian): Jako korelirani elektroni u slojnim organskim materijalima i manganitima: niskofrekventna pobuđenja i nelinearna dinamika; Acronym: SCEinLOM; Leader: Silvia Tomić; Jurisdiction: Croatia; Funding stream: IP
• Document URL: http://link.aps.org/doi/10.1103/PhysRevB.90.195139
• Type of resource: Text
• Access conditions: Open access
• Public note: Copyright (2014) by the American Physical Society. Received 21 July 2014; revised manuscript received 10 October 2014; published 20 November 2014.
• Created on: 2019-12-29 16:09:26