Robustness of the nodal line of Fe₃GeTe₂ to uniaxial strain

We investigate the effect of uniaxial strain on the topological properties of Fe₃GeTe₂ (FGT). Using first-principles calculations, the anomalous Hall conductivity (AHC) and the band structure are obtained for FGT subjected to strains of various magnitudes and directions. We find surprisingly that the AHC is insensitive to the strain. Recalling that in unstrained FGT, the AHC is dominated by the topological nodal line, we examine the fate of the nodal line under the strain and find that the nodal line degeneracy is robust against the strain even when the strain breaks many geometrical symmetries upon which the existence of the nodal line is based according to previous theories. We finally demonstrate using symmetry analysis that the nodal line of FGT can be maintained robustly with respect to the strain.