Formation of As-As Interlayer Bonding in the collapsed tetragonal phase of NaFe2As2 under pressure

Elissaios Stavrou; Xiao-Jia Chen; Artem R Oganov; A F Wang; Y J Yan; X G Luo; X H Chen; Alexander F Goncharov

doi:10.1038/srep09868

Formation of As-As Interlayer Bonding in the collapsed tetragonal phase of NaFe2As2 under pressure

Sci Rep. 2015 May 27:5:9868. doi: 10.1038/srep09868.

Authors

Elissaios Stavrou¹, Xiao-Jia Chen², Artem R Oganov³, A F Wang⁴, Y J Yan⁴, X G Luo⁴, X H Chen⁴, Alexander F Goncharov⁵

Affiliations

¹ Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015, U.S.A.
² 1] Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China [2] Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015, U.S.A [3] Key Laboratory of Materials Physics, Institute of Solid State Physics, CAS, Hefei, 230031, China.
³ 1] Department of Geosciences, Center for Materials by Design, Institute for Advanced Computational Science, Stony Brook University, Stony Brook, NY 11794-2100, U.S.A [2] Moscow Institute of Physics and Technology, 9 Institutskiy lane, Dolgoprudny city, Moscow Region, 141700, Russian Federation [3] School of Materials Science, Northwestern Polytechnical University, Xi'an, 710072, China.
⁴ Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
⁵ 1] Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015, U.S.A [2] Key Laboratory of Materials Physics, Institute of Solid State Physics, CAS, Hefei, 230031, China [3] University of Science and Technology of China, Hefei, 230026, China.

Abstract

NaFe2As2 is investigated experimentally using powder x-ray diffraction and Raman spectroscopy at pressures up to 23 GPa at room temperature and using ab-initio calculations. The results reveal a pressure-induced structural modification at 4 GPa from the starting tetragonal to a collapsed tetragonal phase. We determined the changes in interatomic distances under pressure that allowed us to connect the structural changes and superconductivity. The transition is related to the formation of interlayer As-As bonds at the expense of weakening of Fe-As bonds in agreement with recent theoretical predictions.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.