ARPES view of orbitally resolved quasiparticle lifetimes in iron pnictides

作者：Brouet Veronique^*; LeBoeuf David; Lin Ping Hui; Mansart Joseph; Taleb Ibrahimi Amina; Le Fevre Patrick; Bertran Francois; Forget Anne; Colson Dorothee

来源：Physical Review B, 2016, 93(8): 085137.

DOI：10.1103/PhysRevB.93.085137

We study with angle-resolved photoemission spectroscopy (ARPES) the renormalization and quasiparticle lifetimes of the d(xy) and d(xz)/d(yz) orbitals in two iron pnictides, LiFeAs and Ba(Fe0.92Co0.08)(2)As-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 d(xy), 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 d(xy) exhibit a markedly different behavior than those for d(xz)/d(yz). They have smaller values near E-F and exhibit larger omega and temperature dependences. While the behavior of d(xy) is compatible with a Fermi-liquid description, that 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 about how a Fermi-liquid regime can be established in a multiband system with small effective bandwidths.

• 出版日期2016-2-25
• 单位中国地震局