Fidelity and variability in the interlayer electronic structure of the kagome superconductor CsV3Sb5

TL;DR

This study uses advanced computational methods to analyze the interlayer electronic structure of the kagome superconductor CsV3Sb5, revealing the significant impact of many-body correlations on its kz dispersion and topological properties.

Contribution

It introduces a first-principles approach incorporating nonlocal and dynamical correlations to better understand interlayer interactions in CsV3Sb5.

Findings

Many-body correlations significantly alter interlayer band structure.

Symmetry considerations are crucial for accurate electronic structure analysis.

New insights into kz dispersion support topological invariant calculations.

Abstract

The AV3Sb5 (A = K, Rb, Cs) kagome materials host an interplay of emergent phenomena including superconductivity, charge density wave states, and non-trivial electronic structure topology. The band structures of these materials exhibit a rich variety of features like Dirac crossings, saddle points associated with van Hove singularities, and flat bands prompting significant investigations into the in-plane electronic behavior. However, recent findings including the charge density wave ordering and effects due to pressure or chemical doping point to the importance of understanding interactions between kagome layers. Probing this c-axis electronic structure via experimental methods remains challenging due to limitations of the crystals and, therefore, rigorous computational approaches are necessary to study the interlayer interactions. Here we use first-principles approaches to study the electronic structure of CsV3Sb5 with emphasis on the kz dispersion. We find that the inclusion of nonlocal and dynamical many-body correlation has a substantial impact on the interlayer band structure. We present new band behavior that additionally supports the integration of symmetry in accurately plotting electronic structures and influences further analysis like the calculation of topological invariants.