Chiral phononic and electronic edge modes of EuPtSi

TL;DR

This paper investigates EuPtSi's phononic and electronic properties, revealing chiral edge modes linked to its P2$_{1}$3 symmetry, Weyl and Dirac points, and surface states, with implications for topological phenomena.

Contribution

It provides the first ab initio analysis of EuPtSi's bulk and surface phononic and electronic chiral edge modes related to its symmetry and topological features.

Findings

Presence of spin-1 Weyl point at Γ point

Charge-2 Dirac point at R point

Chiral edge modes in both phononic and electronic spectra

Abstract

Systems with P2$_{1}$3 symmetry are characterized by the realization of chiral edge modes, propagating in one direction along closed loops around some high symmetry points of the Brillouin zone. We study the phononic and electronic properties of EuPtSi, which crystallizes with P2$_{1}$3 symmetry. EuPtSi is also characterized by intriguing magnetic properties, such as the realization of the skyrmion lattice. Here, using ab initio techniques, we study bulk and slab properties of EuPtSi. The bulk phononic and electronic band structures exhibit a spin-1 Weyl point and a charge-2 Dirac point at the $\Gamma$ and R points, respectively. Consequently, the surface states exhibit chiral edge modes. Such features are present in both the phononic and electronic surface spectra. The chiral phononic edge mode is associated with the vibration of the atoms in close vicinity, while the chiral electronic surface states correspond to carrier accumulation at the edge of chiral atomic chains.