Orbital-selective correlations and renormalized electronic structure in LiFeAs

Multiorbital models are important to both the correlation physics and topological behavior of quantum materials. LiFeAs is a prototype iron pnictide suitable for indepth investigation of this issue. Its electronic structure is strikingly different from the prediction of the noninteracting description. Here, a multiorbital Hubbard model for this compound is studied using a $U(1)$ slave spin theory. We demonstrate a new mechanism for a large change in the size of the Fermi surface, namely, orbital selectivity of the energy-level renormalization cooperating with its counterpart in the quasiparticle spectral weight. Using this effect, we show how the dominating features of the electronic structure in LiFeAs are understood in terms of the local correlations alone. Our results reveal a remarkable degree of universality out of the seemingly complex multiorbital building blocks across a broad range of strongly correlated superconductors.