Abstract
In iron-based superconductors (FeSCs), orbital differentiation is an important phenomenon, whereby correlations stronger on the dxy orbital than on the dxz/dyz orbital yield quasiparticles with a dxy orbital character having larger mass renormalization and an abnormal temperature evolution. However, the physical origin of this orbital differentiation is debated between the Hund's coupling-induced unbinding of spin and orbital degrees of freedom and the Hubbard interaction instigated orbital-selective Mott transition. Here we use angle-resolved photoemission spectroscopy to identify an orbital-dependent correlation-induced quasiparticle (QP) anomaly in LiFeAs. The excellent agreement between our photoemission measurements and first-principles many-body theory calculations shows that the orbital-differentiated QP lifetime anomalies in LiFeAs are controlled by the Hund's coupling.
| Original language | English |
|---|---|
| Article number | 201109 |
| Journal | Physical Review B |
| Volume | 94 |
| Issue number | 20 |
| DOIs | |
| State | Published - 2016 |
| Externally published | Yes |
Funding
The experimental work was supported by grants from CAS (XDB07000000, 112111KYS820150017), MOST (2011CBA001000, 2013CB921700, 2015CB921301, 2016YFA0401000, and 2016YFA0300300), and NSFC (11234014, 11220101003, 11274362, and 11674371). H.M. was supported by the Center for Emergent Superconductivity, an Energy Frontier Research Center funded by the U.S. DOE, Office of Basic Energy Sciences. Theoretical work was supported by NSF-DMR 1308141 (Z.P.Y. and G.K.) and NSF-DMR 1405303 (K.H.). Z.P.Y acknowledges the startup fund of Beijing Normal University. This research used resources of the Oak Ridge Leadership Computing Facility, which is a DOE Office of Science User Facility supported under Contract No. DE-AC05-00OR22725.