ARPES view of orbitally resolved quasiparticle lifetimes in iron pnictides

Abstract : We study with angle-resolved photoemission spectroscopy (ARPES) the renormalization and quasiparticle lifetimes of the dxy and dxz/dyz orbitals in two iron pnictides, LiFeAs and Ba(Fe0.92Co0.08)2As2 (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 for 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 dxz/dyz. They have smaller values near EF and exhibit larger ω and temperature dependences. While the behavior of dxy is compatible with a Fermi-liquid description, that is not the case for dxz/dyz. 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 about how a Fermi-liquid regime can be established in a multiband system with small effective bandwidths.
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Contributor : David Le Boeuf <>
Submitted on : Tuesday, February 5, 2019 - 9:43:01 PM
Last modification on : Friday, March 15, 2019 - 1:18:41 AM



Véronique Brouet, David Lebøeuf, 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), ⟨10.1103/PhysRevB.93.085137⟩. ⟨hal-02008804⟩



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