High field magnetic resonant properties of beta'-(ET)2SF5CF2SO3

A systematic electron spin resonance (ESR) investigation of the low temperature regime for the (ET)2SF5CF2SO3 system was performed in the frequency range of ~200-700 GHz, using backward wave oscillator sources, and at fields up to 25 T. Newly acquired access to the high frequency and fields shows experimental ESR results in agreement with the nuclear magnetic resonance (NMR) investigation, revealing evidence that the transition seen at 20 K is not of conventional spin-Peierls order. A significant change of the spin resonance spectrum in beta'-(ET)2SF5CF2SO3 at low temperatures, indicates a transition into a three-dimensional-antiferromagnetic (3D AFM) phase.Comment: 4 pages, 7 figures, minor grammatical change

Interdependency of subsurface carbon distribution and graphene-catalyst interaction.

The dynamics of the graphene-catalyst interaction during chemical vapor deposition are investigated using in situ, time- and depth-resolved X-ray photoelectron spectroscopy, and complementary grand canonical Monte Carlo simulations coupled to a tight-binding model. We thereby reveal the interdependency of the distribution of carbon close to the catalyst surface and the strength of the graphene-catalyst interaction. The strong interaction of epitaxial graphene with Ni(111) causes a depletion of dissolved carbon close to the catalyst surface, which prevents additional layer formation leading to a self-limiting graphene growth behavior for low exposure pressures (10(-6)-10(-3) mbar). A further hydrocarbon pressure increase (to ∼10(-1) mbar) leads to weakening of the graphene-Ni(111) interaction accompanied by additional graphene layer formation, mediated by an increased concentration of near-surface dissolved carbon. We show that growth of more weakly adhered, rotated graphene on Ni(111) is linked to an initially higher level of near-surface carbon compared to the case of epitaxial graphene growth. The key implications of these results for graphene growth control and their relevance to carbon nanotube growth are highlighted in the context of existing literature.R.S.W. acknowledges a Research Fellowship from St. John’s College, Cambridge. S.H. acknowledges funding from ERC grant InsituNANO (No. 279342) and EPSRC under grant GRAPHTED (Ref. EP/K016636/1). We acknowledge the Helmholtz-Zentrum-Berlin Electron storage ring BESSY II for provision of synchrotron radiation at the ISISS beamline and we thank the BESSY staff for continuous support of our experiments. This research was partially supported by the EU FP7 Work Programme under grant Graphene Flagship (No. 604391). PRK acknowledges funding the Cambridge Commonwealth Trust. H.A. and C.B. acknowledge J.-Y. Raty and B. Legrand for fruitful discussions.This is the final published version. It's also available from ACS at http://pubs.acs.org/doi/abs/10.1021/ja505454v

Optical studies of the {beta}{double_prime}-(ET){sub 2}SF{sub 5}RSO{sub 3} R = CH{sub 2}CF{sub 2}, CHFCF{sub 2} and CHF system: Chemical tuning of the counterion

The authors compare the polarized optical spectra of the organic metal {beta}{double_prime}-(ET){sub 2}SF{sub 5}CHFSO{sub 3} and the {beta}{double_prime}-ET{sub 2}SF{sub 5}CHFCF{sub 2}SO{sub 3} metal/insulator material with those of the first fully organic superconductor {beta}{double_prime}-ET{sub 2}SF{sub 5}CH{sub 2}SO{sub 3}. The small chemical modification of the counterion has a dramatic effect on the spectral and charge transport properties of these materials, and they discuss their electronic structure in terms of band structure, many-body effects, and disorder. Based on structural differences in the anion pocket of the three salts, they conclude that the unusual electronic excitations observed in the {beta}{double_prime}-(ET){sub 2}SF{sub 5}CHFCF{sub 2}SO{sub 3} metal/insulator material are caused by disorder-related localization