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arXiv · 0806.4328

First order structural phase transition in CaFe$_2$As$_2$

N. Ni·S. Nandi·A. Kreyssig·A. I. Goldman·E. D. Mun·S. L. Bud'ko·P. C. Canfield
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Abstract

CaFe$_2$As$_2$ has been synthesized and found to form in the tetragonal, ThCr$_2$Si$_2$ structure with lattice parameters $a = 3.912(68) Å$ and $c = 11.667(45) Å$. Upon cooling through 170 K, CaFe$_2$As$_2$ 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. CaFe$_2$As$_2$ is the third member of the AFe$_2$As$_2$ (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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N. Ni, S. Nandi, A. Kreyssig, A. I. Goldman, E. D. Mun, S. L. Bud'ko, P. C. Canfield. 2008-06-26. First order structural phase transition in CaFe$_2$As$_2$. https://doi.org/10.1103/physrevb.78.014523

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