Phase transition observation in Weyl semimetal candidate Mn3Ga epitaxial thin films evidenced by transverse magnetoresistance

Hexagonal antiferromagnetic D0 19 -Mn 3 X ( X = Sn, Ge, Ga) compounds, with a non-collinear kagome spin structure, exhibit novel topological transport properties as colossal longitudinal magnetoresistance and its evolution proportional to the E ⋅ B product. Here, we report on non-vanishing transverse magnetoresistance of strained epitaxial GaN (0001)/Mn 3 Ga films with the magnetic field in the out-of-plane direction and the electric field in the film plane along two perpendicular directions. Strain induces pseudo-electromagnetic fields favoring chiral anomaly and therefore the observation of magnetoresistance. We found an evolution from negative linear to positive quadratic magnetoresistance dependence on the magnetic field in the temperature range from 150 to 300 K, along with a metallic to a narrow band gap semiconductor transition at a temperature of 230 K. First-principles calculations confirmed this transition, proposing a spin structure evolution, and by the implementation of a tight-binding model, based on the Fu-Kane-Mele model, the topological transport properties were analyzed confirming the experimental findings. • Strained epitaxial Mn3Ga thin films were grown by magnetron sputtering. • Non-vanishing transverse magnetoresistance with B in the out-of-plane direction. • Temperature-driven from negative linear to positive quadratic magnetoresistance. • Theoretical calculations propose a spin-structure evolution. • Tight-binding model illustrates a Weyl phase to semiconducting transition.