Structure and properties of tris[bis(ethylenedithio)tetrathiafulvalenium]tetrachloro-copper(II) hydrate, (BEDT-TTF)[sub 3]CuCl[sub 4][center dot]H[sub 2]O: First evidence for coexistence of localized and conduction electrons in a metallic charge-transfer salt

Journal Article · Wed Dec 30 00:00:00 EST 1992 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00053a007· OSTI ID:6204564

Day, P; Kurmoo, M; Mallah, T ^[1]; Marsden, I R; Friend, R H ^[2]; Pratt, F L; Hayes, W ^[3]; Chasseau, D; Gaultier, J; Bravic, G; Ducasse, L ^[4]

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1. Royal Institution of Great Britain, London (United Kingdom)
2. Cavendish Lab., Cambridge (United Kingdom)
3. Clarendon Lab., Oxford (United Kingdom)
4. Universite de Bordeaux I, Talence (France)

The synthesis and physical characterization of a complex of BEDT-TTF [bis(ethylenedithio)tetrathiafulvalenium] with Cu[sup II]Cl[sub 4][sup 2[minus]] are reported. The organic layers contain three crystallographically independent molecules, each 2/3+, and two distinct stacks alternating with each other. The anion is dimerized as [CuCl[sub 4]H[sub 2]O][sub 2], with the Cu[sup II] in a distorted tetrahedral geometry. I is metallic down to 200 mK with a conductivity anisotropy at 300 K of 7:1 (([sigma] [parallel] a-c):([sigma] [perpendicular] 1-c) = 140:20 S cm[sup [minus]1]) within the layers and an EPR spectrum characterized by two lines, one from each spin system (conduction and Cu[sup 2+] localized moments). The g value of the Cu resonance (g[sub [parallel]] = 2.29 and g[sub [perpendicular]] = 2.05) decreases at a gradient of [minus]4 [times] 10[sup [minus]5] K[sup [minus]1] from 4 to 300 K, while that of the conduction electron (g = 2.03--2.05) is temperature independent. The EPR line width increases by 25% and 90% for the Cu and the conduction electrons, respectively, over the same temperature range. The spin susceptibility derived from the Cu resonance fits to a Curie-Weiss law ([Theta] [approx] 1 (1) K) or to a Bleaney-Bowers model for a dimer (J [approx] 4 (1) K), and that of the free carriers shows a Pauli type temperature-independent behavior between 30 and 300 K. Below 30 K, the intensity of the free-carrier resonance falls to 30% of the room-temperature value. From the EPR, there is indication of weak interaction between the two spin systems. From the optical reflectivity data, the width of the conduction band is estimated to be 0.6 eV. A band-structure calculation indicates several zero-transfer integrals, and the Fermi surface has very anisotropic pockets of both electrons and holes, suggesting a semi-metal. 37 refs., 10 figs., 4 tabs.

• OSTI ID: 6204564
• Journal Information: Journal of the American Chemical Society; (United States), Vol. 114:27; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BEDT-TTF
ELECTRON SPIN RESONANCE
MOLECULAR STRUCTURE
COPPER CHLORIDES
COPPER COMPLEXES
ANIONS
ANISOTROPY
CARRIERS
CATIONS
CHEMICAL PREPARATION
CURIE-WEISS LAW
ELECTRIC CONDUCTIVITY
ELECTRONS
FERMI LEVEL
G VALUE
GEOMETRY
HOLES
LAYERS
OPTICAL REFLECTION
RESONANCE
SPIN
STACKS
TEMPERATURE RANGE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
X-RAY DIFFRACTION
ANGULAR MOMENTUM
CHARGED PARTICLES
CHLORIDES
CHLORINE COMPOUNDS
COHERENT SCATTERING
COMPLEXES
COPPER COMPOUNDS
COPPER HALIDES
DIFFRACTION
ELECTRICAL PROPERTIES
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
IONS
LEPTONS
MAGNETIC RESONANCE
MATHEMATICS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANIC SUPERCONDUCTORS
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
REFLECTION
SCATTERING
SUPERCONDUCTORS
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
360602* - Other Materials- Structure & Phase Studies
360606 - Other Materials- Physical Properties- (1992-)