Anisotropic quasiparticle coherence in nematic <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>BaFe</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> studied with strain-dependent ARPES
Heike Pfau, Su-Di Chen, Makoto Hashimoto, N. Gauthier, C. R. Rotundu, J. C. Palmstrom, I. R. Fisher, Sung‐Kwan Mo, Zhi‐Xun Shen, Dong-Hui Lu
Abstract
The hallmark of nematic order in iron-based superconductors is a resistivity anisotropy but it is unclear to which extent quasiparticle dispersions, lifetimes, and coherence contribute. While the lifted degeneracy of the Fe ${d}_{xz}$ and ${d}_{yz}$ dispersions has been studied extensively, only little is known about the two other factors. Here, we combine in situ strain tuning with ARPES and study the nematic response of the spectral weight in ${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$. The symmetry analysis of the ARPES spectra demonstrates that the ${d}_{xz}$ band gains quasiparticle spectral weight compared to the ${d}_{yz}$ band for negative antisymmetric strain $\mathrm{\ensuremath{\Delta}}{\ensuremath{\epsilon}}_{yy}$ suggesting the same response inside the nematic phase. Our results are compatible with a different coherence of the ${d}_{xz}$ and ${d}_{yz}$ orbital within a Hund's metal picture. We also discuss the influence of orbital mixing.