Fermi arcs around magnetic domain walls in a compensated ferrimagnetic Weyl semimetal Ti₂MnAl

Weyl semimetals, a class of three-dimensional topological materials, are known to have Fermi arcs (FAs) as a stable surface state. This boundary state forms open arcs connecting two energy-dispersive point nodes called Weyl points and is protected by a non-zero Chern number. FAs are generally understood as a ‘surface’ state, but it has been pointed out that they also exist around magnetic domain walls (DWs) as a ‘bulk’ state [1]. The structure of FAs around DWs has been analyzed numerically for a simple model, but it is unclear how they appear in realistic materials.

First-principles calculations have shown that Ti₂MnAl is an ideal magnetic Weyl semimetal [2]. Ti₂MnAl is expected to be useful for spintronics because it is compensated ferrimagnetism, and its transition temperature is about 650K. Therefore, further theoretical analyses of Ti₂MnAl are desirable, and an effective tight-binding model was proposed to facilitate these analyses [3]. This model enables us to analyze what is difficult with first-principles calculations.

In this talk, we will use this effective model to confirm that FAs appear under open boundary conditions (OBC) and discuss numerically how FAs appear when DWs are introduced in Ti₂MnAl. As a result, it is clarified that FAs appear differently under OBC and with DWs, and FAs around DWs are protected by a non-zero Chern number.



[1] Y. Araki, A. Yoshida, and K. Nomura, Phys. Rev. B 94, 115312 (2016)

[2] W. Shi et al., Phys. Rev. B 97, 060406 (2018)

[3] T. Meguro et al., J. Phys. Soc. Jpn. 93, 034703 (2024)