Mn-Substituted Topological Phase Transition in Topological Insulator Pt2HgSe3

Abstract

Topological materials have gained a significant interest in recent years due to their unique features, leading to topological insulators (TI), Dirac or Weyl semimetals, etc. The layered material ${\mathrm{Pt}}_2{\mathrm{HgSe}}_3$ is found to be a dual TI characterized by significant spin–orbit coupling and band inversion. We employ a density functional theory (DFT) approach to search a magnetic Weyl semimetal (WSM) by replacing Pt (I) with Mn in ${\mathrm{Pt}}_2{\mathrm{HgSe}}_3$. Here, Mn substitution introduces an exchange field, resulting time-reversal symmetry breaking by lifting spin degeneracy of bulk Dirac states in the band structure. Topological property calculation shows that Mn-substituted ${\mathrm{Pt}}_2{\mathrm{HgSe}}_3$ is a magnetic WSM having 24 Weyl points close to the Fermi level. They are found to influence intrinsic anomalous Hall conductivity that rises up to $\sim$1100 S/cm around 0.8 eV and $\sim$280 S/cm at the Fermi level along easy magnetization axis [001]. Our study shows that substitution of a magnetic atom can play a significant role in tuning the electronic topology of ${\mathrm{Pt}}_2{\mathrm{HgSe}}_3$. We found that bulk ${\mathrm{Pt}}_2{\mathrm{HgSe}}_3$ undergoes topological phase transition from TI to magnetic WSM. It is predicted that Mn-substituted ${\mathrm{Pt}}_2{\mathrm{HgSe}}_3$ can be a promising candidate for high speed spintronics and electronics devices.