Magnetic field effect on topological properties of Dirac semimetals PdTe₂/PtTe₂/PtSe₂

We investigated magnetic field effect on the topological properties of transition metal dichalcogenide Dirac semimetals (DSMs) PdTe₂/PtTe₂/PtSe₂based on Wannier-function-based tight-binding (WFTB) model obtained from first-principles calculations. The DSMs PdTe₂/PtTe₂/PtSe₂undergo a transition from DSMs into Weyl semimetals with four pairs of Weyl points (WPs) in the entire Brillouin zone by splitting Dirac points under external magnetic field. The positions and energies of WPs vary linearly with the strength of thefield under the-axis magnetic field. Under the- and-axisfield, however, the positions of magnetic-field-inducing WPs deviate slightly from theaxis, and theirkcoordinates and energies change in a parabolic-like curve with the increasingfield. However, the system opens an axial gap on theA-Γ axis, and the gap changes with the direction of thefield when the out of-axisfield is applied. When we further apply the magnetic field in theac,bc, andabplanes, the results are more diverse compared to the axial magnetic field. Under theacandbcplanefield, thekand energies of WPs within angleθ= [0°, 90°] andθ= [90°, 180°] are mirror symmetrically distributed. The distribution of WPs shows broken rotational symmetry under theabplanefield due to the difference of non-diagonal part of Hamiltonian. Our theoretical findings can provide a useful guideline for the applications of DSM materials under external magnetic field in the future topological electronic devices.