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

Abstract

We investigated magnetic field effect on the topological properties of transition metal dichalcogenide Dirac semimetals (DSMs) PdTe2/PtTe2/PtSe2 based on Wannier-function-based tight-binding (WFTB) model obtained from first-principles calculations. The DSMs PdTe2/PtTe2/PtSe2 undergo 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 B . The positions and energies of WPs vary linearly with the strength of the B field under the c -axis magnetic field B . Under the a - and b -axis B field, however, the positions of magnetic-field-inducing WPs deviate slightly from the c axis, and their k z coordinates and energies change in a parabolic-like curve with the increasing B field. However, the system opens an axial gap on the A–Γ axis, and the gap changes with the direction of the B field when the out of c -axis B field is applied. When we further apply the magnetic field in the ac, bc, and ab planes, the results are more diverse compared to the axial magnetic field. Under the ac and bc plane B field, the k z and energies of WPs within angle θ = [0°, 90°] and θ = [90°, 180°] are mirror symmetrically distributed. The distribution of WPs shows broken rotational symmetry under the ab plane B field 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.