"Superconductivity at 43 K in an iron-based layered compound
LaO1-xFxFeAs," by Hiroki Takahashi and 5 others, Nature,
453(7193): 376-8, 15 May 2008
[Authors' affiliations: Nihon University, Tokyo, Japan; Tokyo Institute of
Technology, Japan]
Abstract: "The iron- and nickel-based layered compounds
LaOFeP and LaONiP have recently been reported to exhibit low-temperature
superconducting phases with transition temperatures Tc of 3 and 5 K,
respectively. Furthermore, a large increase in the midpoint Tc of up to
similar to 26 K has been realized in the isocrystalline compound LaOFeAs on
doping of fluoride ions at the O2- sites (LaO1-xFxFeAs). Experimental
observations and theoretical studies
suggest that these transitions are related to a magnetic instability, as is
the case for most superconductors based on transition metals. In the
copper-based high-temperature superconductors, as well as in LaOFeAs, an
increase in Tc is often observed as a result of carrier doping in the
two-dimensional electronic structure through ion substitution in the
surrounding insulating layers, suggesting that the application of external
pressure should further increase T-c by enhancing charge transfer between
the insulating and conducting layers. The effects of pressure on these iron
oxypnictide superconductors may be more prominent than those in the
copper-based systems, because the As ion has a greater electronic
polarizability, owing to the covalency of the Fe-As chemical bond, and,
thus, is more compressible than the divalent O2- ion. Here we report that
increasing the pressure causes a steep increase in the onset Tc of F-doped
LaOFeAs, to a maximum of similar to 43 K at similar to 4 GPa. With the
exception of the copper-based high-Tc superconductors, this is the highest
Tc reported to date. The present result, together with the great freedom
available in selecting the constituents of isocrystalline materials with
the general formula LnOTMPn (Ln, Y or rare-earth metal; TM, transition
metal; Pn, group-V, 'pnicogen', element), indicates that the layered iron
oxypnictides are promising as a new material platform for further
exploration of high-temperature superconductivity."
This 2008 report from Nature was cited 30
times in current journal articles indexed by Clarivate
during September-October 2008. Only two other papers published in the last
two years and coded as chemistry in the Hot Papers database (aside from
reviews) attracted higher citation totals during that two-month period;
those two papers also concern iron-based superconductivity. (This
interdisciplinary topic also figures in two
current Top Ten papers categorized under physics.) Prior to the most recent
bimonthly count, citations to the Takahashi et al. paper have
accrued as follows:
July-August 2008: 15 citations
May-June 2008: 2
Total citations to date: 47
SOURCE:
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