Discovery of a pressure-induced ``collapsed'' phase in CaFe$_{2}$As$_{2}$
ORAL
Abstract
Recent investigations of the superconducting iron-arsenide families have highlighted the role of pressure, be it chemical or mechanical, in fostering superconductivity. Here we report that CaFe$_{2}$As$_{2}$ undergoes a pressure-induced transition to a non-magnetic, volume ``collapsed'' tetragonal phase, which becomes superconducting at lower temperature. Spin-polarized total-energy calculations on the collapsed structure reveal that the magnetic Fe moment itself collapses, consistent with the absence of magnetic order in neutron diffraction. -- The support by U.S. DOE (DE-AC02-07CH11358) and NSF (DMR-0306165 and DMR-0805335) is acknowledged.
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Authors
A. Kreyssig$^{1,2}$
$^1$Ames Laboratory; $^2$Dep. of Physics and Astronomy, Iowa State University, Ames
M.A. Green$^{3,4}$
$^3$NIST Center for Neutron Research, Gaithersburg; $^4$Dep. of Materials Science and Engineering, University of Maryland, College Park
Y. Lee$^{1,2}$
G.D. Samolyuk$^{1,2}$
P. Zajdel$^{3,5}$
$^5$Dep. of Chemistry, University College of London, UK
J.W. Lynn$^{3}$
S.L. Bud'ko$^{1,2}$
M.S. Torikachvili$^{6}$
$^6$Dep. of Physics, San Diego State University, San Diego
N. Ni$^{1,2}$
S. Nandi$^{1,2}$
J.B. Le\~{a}o$^{3}$
S.J. Poulton$^{3,4}$
D.N. Argyriou$^{7}$
$^7$Helmholtz-Zentrum Berlin fuer Materialien und Energie, Germany
