# ARPES view of orbitally resolved quasiparticle lifetimes in iron pnictides

4 LNO - Laboratoire Nano-Magnétisme et Oxydes
SPEC - UMR3680 - Service de physique de l'état condensé, IRAMIS - Institut Rayonnement Matière de Saclay
Abstract : We study with ARPES the renormalization and quasiparticle lifetimes of the $d_{xy}$ and $d_{xz}$/$d_{yz}$ orbitals in two iron pnictides, LiFeAs and Ba($Fe_{0.92}$ $Co_{0.08}$)${}_2As_2$ (Co8). We find that both quantities depend on orbital character rather than on the position on the Fermi Surface (for example hole or electron pocket). In LiFeAs, the renormalizations are larger for dxy, while they are similar on both types of orbitals in Co8. The most salient feature, which proved robust against all the ARPES caveats we could think of, is that the lifetimes for dxy exhibit a markedly different behavior than those for $d_{xz}$/$d_{yz}$. They have smaller values near $E_F$ and exhibit larger ω and temperature dependences. While the behavior of $d_{xy}$ is compatible with a Fermi liquid description, it is not the case for $d_{xz}$/$d_{yz}$. This situation should have important consequences for the physics of iron pnictides, which have not been considered up to now. More generally, it raises interesting questions on how a Fermi liquid regime can be established in a multiband system with small effective bandwidths.
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Journal articles
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Cited literature [30 references]

https://hal-cea.archives-ouvertes.fr/cea-01406530
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Submitted on : Thursday, December 1, 2016 - 11:58:54 AM
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1602.07986v1.pdf
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### Citation

Véronique Brouet, David Leboeuf, Ping-Hui Lin, Joseph Mansart, Amina Taleb-Ibrahimi, et al.. ARPES view of orbitally resolved quasiparticle lifetimes in iron pnictides. Physical Review B: Condensed Matter and Materials Physics, American Physical Society, 2016, 93 (8), pp.085137. ⟨10.1103/PhysRevB.93.085137⟩. ⟨cea-01406530⟩

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