Electronic Structures of CaAlSi with Different Stacking AlSi Layers by First-Principles Calculations

TL;DR

This study uses first-principles calculations to explore how different stacking sequences of AlSi layers in CaAlSi influence its electronic structure, revealing effects on Fermi surfaces and electronic anisotropy.

Contribution

It provides a detailed ab-initio analysis of how stacking variations affect electronic properties in CaAlSi, linking structural changes to electronic behavior.

Findings

Buckling and rotation of AlSi layers alter the band structure.

Multistacking increases two-dimensional electronic character.

Structural perturbations lead to disconnected, cylindrical Fermi surfaces.

Abstract

The full-potential linear augmented plane-wave calculations have been applied to investigate the systematic change of electronic structures in CaAlSi due to different stacking sequences of AlSi layers. The present ab-initio calculations have revealed that the multistacking, buckling and 60 degrees rotation of AlSi layer affect the electronic band structure in this system. In particular, such a structural perturbation gives rise to the disconnected and cylindrical Fermi surface along the M-L lines of the hexagonal Brillouin zone. This means that multistacked CaAlSi with the buckling AlSi layers increases degree of two-dimensional electronic characters, and it gives us qualitative understanding for the quite different upper critical field anisotropy between specimens with and without superstructure as reported previously.