Evidences of topological nodal line semimetal in Mn3GaC: Anomalous Hall effect, thermal transport and DFT studies

Abstract

Abstract The non-trivial electronic transport in magnetic topological materials have attracted significant attention. Here, we present evidences of a topological nodal line semimetal in antiperovskite $$\hbox {Mn}_{{3}}$$ GaC along with the experimental studies such as the anomalous Hall effect (AHE), Kondo effect and thermal transport properties (Seebeck and Nernst effects). The upturn in the low-temperature electrical resistivity follows Hamann expression with the Kondo temperature $$T_{K}$$ = 16 K. The scaling analysis of the anomalous Hall conductivity ( $$\sigma _{AHE}$$ ) suggests that the AHE in $$\hbox {Mn}_{{3}}$$ GaC is primarily governed by coexistence of both intrinsic Berry curvature and skew scattering mechanisms. The experimentally observed value of $$\sigma _{AHE}$$ ( $$\sim$$ 50 $$\Omega ^{-1} \text {cm}^{-1}$$ ) is close to the theoretically calculated value. The low temperature Seebeck data suggests the presence of significant contribution of electron–magnon scattering, and a large value of Nernst coefficient is consistent with finite Berry curvature effects in $$\hbox {Mn}_{{3}}$$ GaC. The electronic band structure calculations with spin-orbit coupling, shows the formation of a drumhead-shaped surface states, and the existence of finite number of Weyl nodes, in consistence with the experimental findings.