Topological superconducting domain walls in magnetic Weyl semimetals

Abstract

Recent experimental breakthrough in magnetic Weyl semimetals have inspired exploration on the novel effects of various magnetic structures in these materials. Here we focus on a domain wall structure which connects two uniform domains with different magnetization directions. We study the topological superconducting state in presence of an s-wave superconducting pairing potential. By tuning the chemical potential, we can reach a topological state, where a chiral Majorana mode or zero-energy Majorana bound state is localized at the edges of the domain walls. This property allows a convenient braiding operation of Majorana modes by controlling the dynamics of domain walls.

Tuning the nontrivial topological properties of the Weyl semimetal CeAlSi

“…A similar scenario might occur in CeAlSi, where recently chiral domain walls were found and might be related to the observed topological properties [48]. Furthermore, nontrivial domain walls are predicted to exist in magnetic WSMs [47]. It is conceivable that the internal fields already create tiny displacements at ambient pressure leading to differently oriented magnetic regions due to the presence of strain at domain walls via magnetostriction/magnetoelastic effects [46].…”

“…These lead to strains in the domain walls and create magnetic phases with different textures [46]. In fact, it is theoretically predicted that magnetic WSMs can host nontrivial domain walls [47] and chiral domain walls were indeed recently detected in CeAlSi [48]. The presence of a magnetoelastic effect in CeAlSi suggests a strong response of AHE and LHE to the application of external pressure.…”

Topological features in the ferromagnetic Weyl semimetal CeAlSi: Role of domain walls

“…Going below T C , into the FM state, a magnetic field applied parallel to the [100] direction reveals an AHE, while a [001] field leads to an unexplained hysteretic loop Hall effect (LHE) [36]. In addition, CeAlSi may exhibit nontrivial magnetic domain walls [44]; indeed, chiral domain walls were recently detected in this system [45]. Furthermore, magnetoelastic couplings give rise to picometer displacements in the unit cell due to the internal FM field, which can lead to different domain wall spin textures [46].…”