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arXiv · 1108.1416

Phonon splitting and anomalous enhancement of infrared-active modes in BaFe$_2$As$_2$

A. A. Schafgans·B. C. Pursley·A. D. LaForge·A. S. Sefat·D. Mandrus·D. N. Basov
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Abstract

We present a comprehensive infrared spectroscopic study of lattice dynamics in the pnictide parent compound BaFe$_2$As$_2$. In the tetragonal structural phase, we observe the two degenerate symmetry-allowed in-plane infrared active phonon modes. Following the structural transition from the tetragonal to orthorhombic phase, we observe splitting into four non-degenerate phonon modes and a significant phonon strength enhancement. These detailed data allow us to provide a physical explanation for the anomalous phonon strength enhancement as the result of anisotropic conductivity due to Hund's coupling.

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A. A. Schafgans, B. C. Pursley, A. D. LaForge, A. S. Sefat, D. Mandrus, D. N. Basov. 2011-08-05. Phonon splitting and anomalous enhancement of infrared-active modes in BaFe$_2$As$_2$. https://doi.org/10.1103/physrevb.84.052501

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