Organic superconductor with the highest Tc k-(ET)2Cu[N(CN)2]Cl

Superconductors conduct electricity with little or no resistance. Organic superconductors contain carbon and are less dense than their ceramic or metallic counterparts; they also offer unusual potential for fine-tuning of electrical properties. Argonne National Laboratory long has carried out the major U.S. effort to synthesize and identify organic superconductors. Nearly 100 new superconductors of this type have been produced, with critical temperatures (at which a superconductor loses all electrical resistance) as high as -260 degrees C, or -434 degrees F. Recently, the first superconductor composed entirely of organic components (with no metal atoms) was synthesized, with a transition temperature in this range. Although this remains far lower than the highest known transition temperature for ceramics, scientists still expect that a high-temperature organic superconductor may be possible, such that liquid nitrogen (at -196 degrees C, or -321 degrees F) could be used as the coolant instead of the more costly liquid helium, thus making practical applications more feasible. The new compound has a two-dimensional, layered structure, which may provide significant insight into the nature of superconductivity.

Scientific Impact: These advances will help scientists develop a theory of how organic superconductors work and contribute to the design of new materials with higher transition temperatures. The all-organic material is ideal for studies of magnetic and charge transport properties because there is no possibility of contamination from metallic impurities.

Social Impact: Superconductivity already has important applications, such as medical diagnostic equipment, and many more uses are possible if transition temperatures are high enough. The availability of purely organic superconductors greatly expands the possibilities, especially for applications in which weight is a factor.

Reference: Ambient-Pressure Superconductivity at 2.7 K and Higher Temperatures in Derivatives of beta(ET)₂IBr₂: Synthesis, Structure, and Detection of Superconductivity. Williams, J. M.; Wang, H. H.; Beno, M. A.; Emge, T. J.; Sowa, L. M.; Copps, P. T.; Behroozi, F.; Hall, L. N.; Carlson, K. D.; Crabtree, G. W. Inorg. Chem. 1984, 23, 3839-3841.

A New Ambient-Pressure Organic Superconductor, kappa (ET)₂Cu[N(CN)₂Br, with the Highest Transition Temperature Yet Observed ( Inductive Onset Tc=11.6 K, Resistive Onset=12.5 K) Kini, A. M.; Geiser, U.; Wang, H. H.; Carlson, K. D.; Williams, J. M.; Kwok, W. K.; Vandervoort, K. G.; Thompson, J. E.; Stupka, D. L.; Jung, D.; Whangbo, M.-H. Inorg. Chem. 1990, 29, 2555-2557.

From Semiconductor-Semiconductor Transition (42 K) to the Highest-T_c Organic Superconductor, kappa (ET)₂Cu[N(CN)₂Cl (T_c=12.5 K) Williams, J. M.; Kini, A. M.; Wang, H. H.; Carlson, K. D.; Geiser, U.; Montgomery, L. K.; Pyrka, G. J.; Watkins, D. M.; Kommers, J. M.; Boryschuk, S. J.; Strieby Crouch, A. V.; Kwok, W. K.; Schirber, J. E.; Overmyer, D. L.; Jung, D.; Whangbo, M.-H. Inorg. Chem. 1990, 29, 3272-3274.

The First Organic Cation-radical Salt Superconductor (T_c=4 K) with an Organometallic Anion: Superconductivity, Synthesis and Structure of kappa (ET)₂M(CF₃)4(C2H₃X₃). Schlueter, J. A.; Geiser, U.; Williams, J. M.; Wang, H. H.; Kwok, W. K.;Fendrich, J. A.; Carlson, K. D.; Achenbach, C. A.; Dudek, J. D.; Naumann, D.; Roy, T.; Schirber, J. E.; Bayless, W. R. J. Chem. Soc., Chem. Commun. 1994, 1599-1600.

Superconductivity at 5.2 K in an Electron Donor Radical Salt of Bis (ethylenedithio) tetrathiafulvalene (BEDT-TTF) with the Novel Polyfluorinated Organic Anion beta (ET)₂SF₅CH₂CF₂SO₃) Geiser, U.; Schlueter, J. A.; Wang, H. H.; Kini, A. M.; Williams, J. M.; Sche, P. P.; Zakowicz, H. I.; VanZile, M. L.; Dudek, J. D.; Nixon, P. G.; Winter, R.W.; Gard, G. L.; Ren, J.; Whangbo, M.-H. J. Am. Chem. Soc. 1996, 118, 9996-9997.

URL: http://www.msd.anl.gov/groups/occ/decades.htm

Technical Contact: Don Freeburn, Office of Basic Energy Sciences, 301-903-3156

Press Contact: Jeff Sherwood, DOE Office of Public Affairs, 202-586-5806

SC-Funding Office: Office of Basic Energy Sciences