From semiconductor-semiconductor transition (42 K) to the highest-Tc organic superconductor, .kappa.-(ET)2Cu[N(CN)2]Cl (Tc = 12.5 K)

Williams, Jack M.; Kini, A. M.; Wang, H.H.; Carlson, K. Douglas; Geiser, U.; Montgomery, L. K.; Pyrka, Gloria J.; Watkins, D. M.; Kommers, J. M.; Boryschuk, S. J.; Crouch, A.V. Strieby; Kwok, W. K.; Schirber, J. E.; Overmyer, D. L.; Jung, D.; Whangbo, Myung‐Hwan

doi:10.1021/ic00343a003

Cited by 471 publications

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“…The electronic properties of the salts are caused by various crystalline modifications, such as α-, α'-, α''-, θ-, κ-, β-, β'-, and β''-types, which exhibit the transport properties of semiconductors, metals, or even superconductors in relation to their structures and often undergo electronically and structurally reversible phase transitions in relation to pressure and/or temperature [2][3][4]. The electronic properties of the BEDT-TTF layers in these crystals depend dramatically on the sulfur-sulfur overlaps of neighboring BEDT-TTF molecules, which can also be changed by anion substitution or possibly by 2 (Cu(N(CN) 2 )Cl 1−x Br x exhibits superconductivity under hydrostatic pressure.…”

Section: Introductionmentioning

confidence: 99%

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New BEDT-TTF Radical Cation Salt with Mixed Anions: α'-[BEDT-TTF]2[CuBr2]0.4[CuCl2]0.6

Kubo

Yamashita

2012

Crystals

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Abstract:A new mixed-anion crystal composed of BEDT-TTF radical cation salt [BEDT-TTF] 2 (CuBr 2 ) 0.4 (CuCl 2 ) 0.6 with an α'-type donor arrangement with a formal charge of +0.5 per BEDT-TTF was prepared by using a chemical oxidation method and characterized by using X-ray diffraction, four-probe electrical resistivity measurements (semiconductor: ρ rt = 2 × 10 2 Ω cm, E a = 0.2 eV), and energy band calculations. The results showed that this system had a quasi-one dimensional Fermi surface.

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Section: Introductionmentioning

confidence: 99%

“…The critical pressure for the occurrence of superconductivity (P crit = 0.029 GPa for x = 0) is lowered by increasing Br − content [5,6]. The metal-insulator transition temperature for θ-[BEDT-TTF] 2 (Rb 1−x Cs x )Zn(SCN) 4 depends on the ratio of Rb and Cs [7]. The [5,6].…”

Section: Introductionmentioning

confidence: 99%

New BEDT-TTF Radical Cation Salt with Mixed Anions: α'-[BEDT-TTF]2[CuBr2]0.4[CuCl2]0.6

Kubo

Yamashita

2012

Crystals

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“…The electronic band is effectively half filled and the system is on the insulating side of a nearby metal-insulator Mott transition. The two chemically equivalent organic ET layers [10,11], A and B (Fig. 1) are separated by Cu[N(CN) 2 ]Cl polymer sheets.…”

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confidence: 99%

Magnetic fluctuations above the Néel temperature in κ‐(BEDT‐TTF)₂Cu[N(CN)₂]Cl, a quasi‐2D Heisenberg antiferromagnet with Dzyaloshinskii–Moriya interaction

Antal

Fehér

Náfrádi

et al. 2012

Physica Status Solidi (b)

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Field-induced antiferromagnetic (AF) fluctuations and magnetization are observed above the (zero-field) ordering temperature, TN = 23 K by electron spin resonance in κ-(BEDT-TTF)2Cu[N(CN)2]Cl, a quasi two-dimensional antiferromagnet with a large isotropic Heisenberg exchange interaction. The Dzyaloshinskii-Moriya (DM) interaction is the main source of anisotropy, the exchange anisotropy and the interlayer coupling are very weak. The AF magnetization is induced by magnetic fields perpendicular to the DM vector; parallel fields have no effect. The different orientation of the DM vectors and the g factor tensors in adjacent layers allows the distinction between interlayer and intralayer correlations. Magnetic fields induce the AF magnetization independently in adjacent layers. We suggest that the phase transition temperature, TN is determined by intralayer interactions alone.PACS numbers: 76.30.-v, 76.50+g, 75.30-m One-dimensional (1D) magnets, i.e., isolated chains of magnetic atoms or molecules have no ordering phase transitions while 3D magnets order at finite temperatures, T N . Magnetic ordering in two dimensions, i.e., in isolated planes, is a delicate question [1]. Theory predicts for most anisotropic two-dimensional (2D) magnets a phase transition at finite T N except if ordering breaks a continuous symmetry. The case of S = 1/2 anisotropic Heisenberg antiferromagnets is complicated [2]. Experiments on low dimensional magnets with negligible interactions between the magnetic chains or planes are rare. The magnetic-field-induced change in the excitation spectrum of 1D Heisenberg chains [3,4] agrees with theory [5,6]. Field-induced magnetism has also been studied in a quasi 2D S = 1 dimer system [7]. The present experiments are on a quasi 2D, S = 1/2 magnet where the continuous symmetry is broken by a very small anisotropy and the applied magnetic field, H.is a layered spin 1/2 Heisenberg antiferromagnet with a magnetic ordering transition [8] at T N = 23 K measured [9] in H = 0. The ET molecules are arranged in a 2D lattice of singly charged dimers. The electronic band is effectively half filled and the system is on the insulating side of a nearby metal-insulator Mott transition. The two chemically equivalent organic ET layers [10, 11], A and B (Fig. 1) are separated by Cu[N(CN) 2 ]Cl polymer sheets.The ordered state is well described by two-sublattice antiferromagnetic layers weakly coupled through the polymeric sheets [12]. The measured macroscopic parameter of the in-plane isotropic exchange, (J/2) i,j S i · S j is λM 0 = 2J/(gµ B ) = 450 T [8,13]. The magnitude of the antisymmetric Dzyaloshinskii-Moriya (DM) ex- Kagawa et al. [9] pointed out that in κ-ET 2 -Cl the DM interaction plays an important role above T N . In magnetic fields (unless parallel to the DM vector) the phase transition is replaced by a crossover. In this case the AF magnetization remains finite above T N and there is a weak ferromagnetic moment along H at all temperatures. They measured µ s , the field-induced staggered static magne...

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“…High quality single crystals of the κ-ET-Cl and κ-ETBr were grown by standard electrochemical methods 22,23 . The crystallography and the band structure of these compounds are reviewed in Ref.…”

Section: Methodsmentioning

confidence: 99%

Localized states in the Mott insulatorκ-(BEDT–TTF)2Cu[N(CN)2]Cl as probed by photoluminescence

2013

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From semiconductor-semiconductor transition (42 K) to the highest-Tc organic superconductor, .kappa.-(ET)2Cu[N(CN)2]Cl (Tc = 12.5 K)

Cited by 471 publications

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New BEDT-TTF Radical Cation Salt with Mixed Anions: α'-[BEDT-TTF]2[CuBr2]0.4[CuCl2]0.6

New BEDT-TTF Radical Cation Salt with Mixed Anions: α'-[BEDT-TTF]2[CuBr2]0.4[CuCl2]0.6

Magnetic fluctuations above the Néel temperature in κ‐(BEDT‐TTF)₂Cu[N(CN)₂]Cl, a quasi‐2D Heisenberg antiferromagnet with Dzyaloshinskii–Moriya interaction

Localized states in the Mott insulatorκ-(BEDT–TTF)2Cu[N(CN)2]Cl as probed by photoluminescence

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From semiconductor-semiconductor transition (42 K) to the highest-Tc organic superconductor, .kappa.-(ET)2Cu[N(CN)2]Cl (Tc = 12.5 K)

Cited by 471 publications

References 0 publications

New BEDT-TTF Radical Cation Salt with Mixed Anions: α'-[BEDT-TTF]2[CuBr2]0.4[CuCl2]0.6

New BEDT-TTF Radical Cation Salt with Mixed Anions: α'-[BEDT-TTF]2[CuBr2]0.4[CuCl2]0.6

Magnetic fluctuations above the Néel temperature in κ‐(BEDT‐TTF)2Cu[N(CN)2]Cl, a quasi‐2D Heisenberg antiferromagnet with Dzyaloshinskii–Moriya interaction

Localized states in the Mott insulatorκ-(BEDT–TTF)2Cu[N(CN)2]Cl as probed by photoluminescence

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Magnetic fluctuations above the Néel temperature in κ‐(BEDT‐TTF)₂Cu[N(CN)₂]Cl, a quasi‐2D Heisenberg antiferromagnet with Dzyaloshinskii–Moriya interaction