Journal of the American Chemical Society
Communication
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κ-phase salts of BEDT-TTF, the properties are tuned by a
combination of physical pressure and anion substitution
(chemical pressure), generating a variety of phases, including
superconductivity.21 FBBO may represent a benchmark
example of a new class of strongly correlated materials based
on neutral molecular radicals. Unlike charge transfer salts,
where the building blocks are dimeric radical cations, neutral
1
radicals are true f = /2 materials, in which the absence of
counteranions results in a simpler structure. So far, only a
limited section of the phase diagram of FBBO has been
examined, but already it displays properties common to these
other classes of materials. That is, it possesses a highly 2D
electronic structure, an ordered AFM phase at low T for P < Pc,
and a metallic phase at high T for P > Pc. With further
exploration of FBBO, as well as related neutral radical materials,
there is little doubt that interesting physics will emerge.
ASSOCIATED CONTENT
■
S
* Supporting Information
Experimental details and characterization data. This material is
AUTHOR INFORMATION
■
Corresponding Author
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank the NSERC (Canada) and the EPSRC (U.K., Grant
No: EP/C536436/1) for financial support, a NSERC
postdoctoral fellowship to C.M.R. and a NSERC graduate
scholarship to S.M.W. We also thank the Government of
Canada for a Tier I Canada Research Chair to J.S.T., the
Diamond Light Source for beam time and Professor Bill Clegg
for help with processing the DLS data.
(17) The EHT method probably overestimates the bandwidth of
FBBO. Preliminary DFT calculations suggest a smaller W, in keeping
with the measured valence band photoelectron spectrum and the value
of U estimated electrochemically. Tse, J. S., unpublished results.
(18) (a) Bryan, C. D.; Cordes, A. W.; Haddon, R. C.; Glarum, S. H.;
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R. C.; MacKinnon, C. D.; Oakley, R. T.; Palstra, T. T. M.; Perel, A. S. J.
Am. Chem. Soc. 1995, 117, 6880.
(19) Leitch, A. A.; Lekin, K.; Winter, S. M.; Downie, L. E.; Tsuruda,
H.; Tse, J. S.; Mito, M.; Desgreniers, S.; Dube, P. A.; Zhang, S.; Liu,
Q.; Jin, C.; Ohishi, Y.; Oakley, R. T. J. Am. Chem. Soc. 2011, 133, 6051.
(20) (a) Norman, M. R. Science 2011, 332, 196. (b) Si, Q.; Steglich,
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2005, 433, 226. (d) Dressel, M. J. Phys.: Condens. Matter 2011, 23,
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