Anomalous transverse effects in nodal line compounds Co2TaX (X = Al, Ga)

The magnetic ground state, electronic, and elastic properties of Co2TaX (X = Al, Ga) are investigated using Density functional theory calculations. The compounds are found to possess mechanical and dynamical stability. Both the compounds exhibit nodal line features in the majority spin channel without the inclusion of spin-orbit coupling (SOC) and become gapped lines when SOC is added. The anomalous Hall effect and anomalous Nernst effect caused by Berry curvature are investigated. Within the region of ±300meV around Fermi level, the maximum values of anomalous Hall conductivities (AHC) are −602.8 S/cm and −593.8 S/cm, while anomalous Nernst conductivities (ANC) are -4.989 Am−1K−1 and 4.934 Am−1K−1 respectively, for Co2TaX (X = Al, Ga) compounds. Through the Heisenberg magnetic exchange interactions, the Curie temperatures (TC) for both Co2TaX (X = Al, Ga) compounds are calculated to be 560.7 K and 556.3 K within the mean-field approximation (MFA). The magneto-optical response is also examined, and the polar Kerr rotation angles for Co2TaAl and Co2TaGa at normal incidence were determined to be 0.11° and 1.35°, respectively. As a result, this study may pave the way for precise property engineering in real-world applications.