Structure and properties of a new conducting organic charge-transfer salt β-(BEDT-TTF) 2AuBr 2
Abstract
A new conducting organic charge-transfer salt, β-(BEDT-TTF) 2AuBr 2 has been synthesised and its crystal structure determined. Single crystal four-probe conductivity has been measured at ambient and applied pressures from 300-1.4 K and EPR spectroscopy from 300-4.2 K. β-(BEDT-TTF) 2AuBr 2 crystallises in P overline1 ( Z=1) with a = 9.020(1), b = 5.707(9), c = 16.320(1) Å; ∝ = 97.60(1), β = 92.12(1), γ = 102.89(1) o; V = 811.8(2) Å3. While the electronic properties are two-dimensional, the molecular packing of the BEDT-TTF molecules is slightly different from that found in other β-phase BEDT-TTF salts with triatomic counterions. β-(BEDT-TTF) 2AuBr 2 is metallic to 1.4K at pressures up to 5.6 kbar although at all pressures studied there is appreciable hysteresis in the cooling and warming cycles of the conductivity between 6 and 14K. Abrupt transitions in the temperature dependence of both the peak-to-peak EPR linewidth and integrated signal intensity occur near 20K. The possibility of a low temperature structural modification is discussed.
- Publication:
-
Solid State Communications
- Pub Date:
- February 1987
- DOI:
- 10.1016/0038-1098(87)90491-1
- Bibcode:
- 1987SSCom..61..459K