Naslov
WHAT IS THE ORIGIN OF ANOMALOUS DIELECTRIC RESPONSE IN THE SPIN LIQUID ORGANIC SYSTEM kappa-(BEDT-TTF)2Cu2(CN)3: AN IN-DEPTH STUDY OF ANISOTROPIC CHARGE DYNAMICS

Autori
Pinterić, Marko ; Čulo, Matija ; Milat, Ognjen ; Basletić, Mario ; Korin-Hamzić, Bojana ; Tafra, Emil ; Hamzić, Amir ; Ivek, Tomislav ; Dressel, Martin ; Schlueter, John A. ; Miyagawa, K. ; Kanoda, Kazushi ; Tomić, Silvia

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

Izvornik
International Research School and Workshop on Electronic Crystals ECRYS 2014 / Kirova, Natasha - Orsay : LPTMS, CNRS and University Paris-Sud, 2014, 87-87

Skup
International Research School and Workshop on Electronic Crystals ECRYS 2014

Mjesto i datum
Cargèse, Francuska, 11.08.2014. - 23.08.2014

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
2D molecular solids; anomalous dielectric relaxation; charge ordering; ferroelectricity; Mott dimer insulator; anisotropic charge response

Sažetak
Novel forms of the low-temperature phases in the two-dimensional molecular solids with competing interactions between charges, spins and lattice, in particular those featuring anomalous dielectric relaxation, have been the focus of intense activity in recent years. Open issues concern the nature of collective charge excitations as well as their coupling to applied ac and dc electric fields. The charge response is reasonably well understood by now in the charge-ordered phase with the formation of ferroelectric-like domains below the metal-to-insulator phase transition [1, 2]. Conversely, the dielectric response observed in dimer Mott insulator phases with no charge ordering [3] is rather intriguing [4, 5, 6, 7]. In this presentation we review our in-depth study (dc conductivity, Hall effect and dielectric spectroscopy) of the anisotropic charge response in an unconventional Mott insulator with spin liquid kappa-(BEDT-TTF)2Cu2(CN)3. Variable-range hopping transport within molecular planes in dc limit and an anomalously broad anisotropic dielectric relaxation in audio-frequency range demonstrate the inherent heterogeneity present in nominally pure single crystals of kappa-(BEDT-TTF)2Cu2(CN)3. The relaxation bears fingerprints of relaxor ferroelectricity: a gradual slowing down becomes dominated by tunneling at low temperatures and at the bifurcation temperature anomalous features in dielectric constant, mean relaxation time and spectral broadening are detected. We argue that the observed behavior is due to a strong charge-spin-lattice coupling reflecting the gradual emergence of random potential and domain structure originated in the anion network. [1] T.Ivek et al., Phys.Rev.B83, 165128 (2011). [2] T.Ivek et al., Phys.Rev.B86, 245125 (2012). [3] K.Sedlmeier et al., Phys.Rev.B86, 245103 (2012). [4] M.Abdel-Jawad et al., Phys.Rev.B82, 125119 (2010). [5] S.Iguchi et al., Phys.Rev.B87, 075107 (2013). [6] P.Lunkenheimer et al., Nat. Mater. 11, 755 (2012). [7] S.Tomic et al., J.Phys.: Condens.Matter 25, 436004 (2013). [8] M.Pinteric et al., to be submitted (2014).

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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