Naslov
Temperature dependence of anisotropic resistivity and hall coefficient of the spin-liquid candidate κ-(BEDT-TTF)2Cu2(CN)3

Autori
Čulo, Matija ; Tafra, Emil ; Basletić, Mario ; Tomić, Silvia ; Hamzić, Amir ; Korin-Hamzić, Bojana ; Dressel, Martin ; Schlueter, John A.

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
International Research School and Workshop on Electronic Crystals ECRYS 2014 / Kirova, Natasha - Orsay : University Paris-Sud, 11, 2014, 141-141

Skup
International Research School and Workshop on Electronic Crystals ECRYS 2014

Mjesto i datum
Cargèse, Francuska, 11.08.2014. - 23.08.2014

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
organic conductors; strongly correlated electron systems; magnetotransport properties; variable range hopping

Sažetak
The two-dimensional organic charge-transfer salts based on BEDT-TTF molecules in a κ-type dimer lattice arrangement have been intensively studied due to the complex interplay between electronic correlation, effects of low dimensionality and spin frustration. In that sense, κ-(BEDT-TTF)2Cu2(CN)3 is of particular interest because no indication of magnetic order at ambient pressure was observed down to lowest temperatures and it is therefore considered as one of the first examples of a quantum spin-liquid state [1] suggested by Anderson 40 years ago [2]. The ratio of the on-site Coulomb repulsion U and the hopping integral t (U/t = 7.3) indicates that this system lies near the Mott transition, and the tight-binding calculations, based on crystallographic data at room temperature, suggest that the ratio of inter-dimer transfer integrals t′/t = 0.83 is very close to one [3]. Consequently, this system could be described as a half-filled band with strong spin frustration that prohibits the magnetic ordering and suggests a spin liquid ground state. In previous measurements various anomalies were observed upon approaching the spin-liquid state from high temperatures (changes in the 1H-NMR relaxation rate around 200 K to 150 K [4] or the thermopower at 150 K [5]). These findings call for Hall effect measurements in order to learn about the carrier density. We have investigated the anisotropy of dc resistivity for 20 K < T < 300 K and the temperature dependence of the Hall coefficient (RH) for 50 K < T < 300 K and in magnetic fields up to 5 T. Resistivity shows a small in-plane, and a large out-of-plane anisotropy. The positive (hole-like) Hall coefficient exhibits a considerable temperature dependence following the similar behavior of the in-plane resistivity, and it does not show any significant anomaly in the investigated temperature region. Around room temperature, the value of RH approaches the one calculated for two holes per unit cell. In the temperature range from 50 K to 300 K the corresponding change in effective number of carriers, which contribute to transport properties, increase about two orders of magnitude, whereas the Hall mobility does not change more than three times. [1] Y. Shimizu, et al., Phys. Rev. Lett. 91, (2003) 107001. [2] P. W. Anderson, Mat. Res. Bull. 8, (1973) 153. [3] H. C. Kandpal, et al., Phys. Rev. Lett. 103, (2009) 067004. [4] A. Kawamoto et al., Phys.Rev. B 70, (2004) 060510 [5] T. Komatsu, et al, J. Phys. Soc. Jpn. 65, (1996) 1340.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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