First order structural phase transition in CaFe2As2
Abstract
CaFe2As2 has been synthesized and found to form in the tetragonal, ThCr2Si2 structure with lattice parameters a = 3.912(68) and c = 11.667(45) . Upon cooling through 170 K, CaFe2As2 undergoes a first order, structural phase transition to a low temperature, orthorhombic phase with a 2 - 3 K range of hysteresis and coexistence. This transition is clearly evident in microscopic, thermodynamic and transport measurements. CaFe2As2 is the third member of the AFe2As2 (A = Ba, Sr, Ca) family to exhibit such a dramatic phase transition and is a promising candidate for studies of doping induced superconductivity.
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