Satoshi Yamashita, E. Yesil, Luming Zhang, Tetsuya Nomoto, Hiroki Akutsu, A. Krivchikov, Yasuhiro Nakazawa
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引用次数: 0
Abstract
The nonlinear electric conductivity of κ-(BEDT-TTF)4Hg2.89Br8, which is known as a hole-doped spin liquid, has been observed by single crystal transport measurements using dc and ac excitations. This compound is known as a charge transfer complex with strong magnetic fluctuations accompanied by electron mass enhancement at ambient pressure. We discuss the nonlinear dc conductivity drastically emerging below 100 K. We also performed ac impedance measurements of this compound and compared the results with those of a typical dimer-Mott compound of deuterated κ-(d8-BEDT-TTF)2Cu[N(CN)2]Br, located just near the Mott boundary. The analyses of the Nyquist plots of κ-(d8-BEDT-TTF)2Cu[N(CN)2]Br and κ-(BEDT-TTF)4Hg2.89Br8 reveal qualitatively different features. The former shows a behavior pertinent to the inhomogeneous distribution of domains due to a mixing of metal and insulating phases, taking into account the influence of the proximity effect, while the doped spin liquid has a distinct semicircle-type frequency dependence in its Nyquist plot in the whole temperature range studied. We conclude that the nonlinear conductivity is intrinsically peculiar to the doped dimer Mott system, where the charge degrees of freedom dominate the itinerancy. We attribute the anomalous features, such as non-Fermi liquid behavior, heat capacity enhancement, and strong antiferromagnetic fluctuations in κ-(BEDT-TTF)4Hg2.89Br8, to a kind of charge confinement effect retained in the hole-doped spin-liquid state.
期刊介绍:
Guided by an international editorial board, Low Temperature Physics (LTP) communicates the results of important experimental and theoretical studies conducted at low temperatures. LTP offers key work in such areas as superconductivity, magnetism, lattice dynamics, quantum liquids and crystals, cryocrystals, low-dimensional and disordered systems, electronic properties of normal metals and alloys, and critical phenomena. The journal publishes original articles on new experimental and theoretical results as well as review articles, brief communications, memoirs, and biographies.
Low Temperature Physics, a translation of the copyrighted Journal FIZIKA NIZKIKH TEMPERATUR, is a monthly journal containing English reports of current research in the field of the low temperature physics. The translation began with the 1975 issues. One volume is published annually beginning with the January issues.