Surface States and Anisotropic Magnetoresistance in Nodal-Line Semimetal ZrGeTe

We investigate the electronic structure, anisotropic magnetoresistance (MR) and topological properties of nodal-line semimetal ZrGeTe using first-principles calculations. The band structure reveals a nodal line predominantly derived from the d orbitals of Zr and the p orbitals of Te and Ge. Surface state calculations confirm the topological signature through pronounced drumhead surface states, which exhibit a clear spin splitting after including spin-orbit coupling. The anisotropic MR is analyzed based on the calculated Fermi surface geometry. With current along the c-axis and magnetic field rotating in the a-b plane, the MR reflects the C_4z symmetry of the Fermi surface, reaching a maximum at φ = 0 and a minimum at φ = π/4. With current along the a or b axis and field rotating in the a-c plane, a butterfly-shaped MR pattern emerges, consistent with the twofold Fermi surface symmetry. Our results demonstrate that the complex Fermi surface geometry profoundly shapes the anisotropic MR of ZrGeTe.