Journal article
Structural, electrical, magnetic, and optical properties of bis-benzene-1,2-dithiolato-Au(IV) crystals
Department of Physics, Technical University of Denmark1
Risø National Laboratory for Sustainable Energy, Technical University of Denmark2
Ludwig Maximilian University of Munich3
Quantum Physics and Information Technology, Department of Physics, Technical University of Denmark4
X-ray Crystallography, Department of Chemistry, Technical University of Denmark5
Department of Chemistry, Technical University of Denmark6
Analysis of x-ray diffraction from a single crystal of bis-benzene-1,2-dithiolato-Au(IV) [Au(bdt)(2)] at 125 K reveals a superstructure along the stacks of Au(bdt)(2) molecules corresponding to a dimerization of the molecules along the stack. Within a dimer, intermolecular sulfur-sulfur contacts are shortened from 3.7 to 3.6 Angstrom whereas a lengthening to about 3.8 Angstrom is found between dimers.
Electrical resistivity measured by a four-probe method between 230 and 450 K uncovers an activated resistivity with a characteristic energy of 0.30 eV. The room-temperature conductivity at zero applied pressure is 0.11 Omega(-1) m(-1) rising smoothly to 0.67 Omega(-1) m(-1) at 0.55 GPa isotropic pressure.
The magnetic susceptibility chi is low compared to the spin susceptibility of a system with one free spin per molecule. An activated behavior of chi is observed, which gives rise to a monotonic increase in chi at between 275 and 420 K. Reflectivity measurements along the b axis (stacking direction) of a single crystal of Au(bdt)(2) shows a transition around 5000 cm(-1) (0.6 eV) possessing an oscillator strength approximate to 0.5 electron/molecule.
Along the c axis an absorption centered around 8000 cm(-1) is observed. The first transition (5000 cm(-1)) is attributed to an intermolecular charge-transfer process while the latter transition (8000 cm(-1)) most likely corresponds to an intramolecular excitation. The physical data presented are discussed in the context of a soft Mott insulator.
Language: | English |
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Year: | 1996 |
Pages: | 1773-1778 |
ISSN: | 10953795 , 01631829 , 1550235x , 10980121 and 24699950 |
Types: | Journal article |
DOI: | 10.1103/PhysRevB.53.1773 |