Inelastic neutron scattering study of a nonmagnetic collapsed tetragonal phase of CaFe2As2: Evidence of the impact of spin fluctuations on superconductivity in the iron-arsenide compounds

• Published in: Physical review letters 2013-01, Vol.111 (22)
• Main Authors: Soh, Jing Han, Tucker, G. S., Pratt, Daniel K, Abernathy, Douglas L, Stone, Matthew B, Ran, S., Budko, S L, Canfield, P. C., Kreyssig, A., McQueeney, R. J., Goldman, A. I.
• Format: Article
• Language: English
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.111.227002

The relationship between antiferromagnetic spin fluctuations and superconductivity has become a central topic of research in studies of superconductivity in the iron pnictides. We present unambiguous evidence of the absence of magnetic fluctuations in the non-superconducting collapsed tetragonal phase of CaFe2As2 via inelas- tic neutron scattering time-of-flight data, which is consistent with the view that spin fluctuations are a necessary ingredient for unconventional superconductivity in the iron pnictides. We demonstrate that the collapsed tetrag- onal phase of CaFe2As2 is non-magnetic, and discuss this result in light of recent reports of high-temperature superconductivity in the collapsed tetragonal phase of closely related compounds.