Mn-Substituted Topological Phase Transition in Topological Insulator Pt₂HgSe₃

Topological materials are intriguing for electronics and spintronics due to their unique band structure with Dirac and Weyl points, leading to exotic phenomena such as chiral anomalies and Fermi arcs. The layered compound Pt₂HgSe₃ is a dual topological insulator characterized by significant spin-orbit coupling and band inversion around the Fermi level. In search of topological materials like Weyl semimetal (WSM) Weyl metals, Mn is doped in Pt site of Pt₂HgSe₃ by using density functional theory (DFT) approach. Substitution of Pt atom with Mn dopant introduces an exchange field which breaks time-reversal symmetry and lifts the spin degeneracy of the bulk Dirac states. Our DFT calculations reveal that beyond a critical exchange strength, the band gap closes and reopens with the formation of pairs of Weyl nodes carrying opposite chirality. The Wannier-interpolated Hamiltonian, analyzed using full potential local orbital (FPLO), confirms the appearance of surface Fermi arc states connecting the projections of the Weyl nodes. Our topological calculation shows that PtMnHgSe₃ is a magnetic Weyl semimetal. Moreover, the computed Berry curvature and anomalous Hall conductivity of Pt₂HgSe₃ establish the emergence of a time-reversal-symmetry-broken magnetic Weyl semimetal phase. The emergence of Weyl points gives rise to a large intrinsic anomalous Hall conductivity of up to ∼1000 S/cm below 0.8 eV above the Fermi level and ∼250 S/cm at the Fermi level. These findings demonstrate that magnetic doping provides an effective route to tune the electronic topology of Pt₂HgSe₃, offering a promising platform for realizing magnetic WSM and studying topological transport phenomena such as the anomalous Hall and chiral anomaly effects. Here our calculation shows that bulk jacutingaite undergoes topological transition from Topological insulator to magnetic Weyl semimetal and we predict that MnPtHgSe₃ can be a promising candidate for high speed spintronics and electronics devices.