The effects of k-dependent self-energy in the electronic structure of correlated materials

TL;DR

This paper investigates how k-dependent self-energy influences the electronic structure of correlated materials, revealing that nonlocal effects are significant even in narrow-band systems like SrVO3, contrary to common assumptions.

Contribution

It demonstrates the importance of nonlocal self-energy in narrow-band materials, challenging the assumption that self-energy is predominantly local in such systems.

Findings

Nonlocal self-energy significantly affects narrow-band materials.

Strong cancellation occurs between frequency- and momentum-dependent self-energy effects.

Nonlocal effects are important even in materials with narrow bands like SrVO3.

Abstract

It is known from self-energy calculations in the electron gas and sp materials based on the GW approximation that a typical quasiparticle renormalization factor (Z factor) is approximately 0.7-0.8. Band narrowing in electron gas at rs = 4 due to correlation effects, however, is only approximately 10%, significantly smaller than the Z factor would suggest. The band narrowing is determined by the frequency-dependent self-energy, giving the Z factor, and the momentum-dependent or nonlocal self-energy. The results for the electron gas point to a strong cancellation between the effects of frequency- and momentum-dependent self-energy. It is often assumed that for systems with a nar- row band the self-energy is local. In this work we show that even for narrow-band materials, such as SrVO3, the nonlocal self-energy is important.