Magnetism and Magneto-transport in the Kagome Antiferromagnet Weyl Metal Mn₃Ge

We perform classical Monte Carlo and stochastic Landau-Lifshitz-Gilbert simulations to study temperature dependent magnetism of Kagome antiferromagnet Weyl metal Mn₃Ge and find that a long range chiral order sets in at a transition temperature well below the N{\'e}el temperature.  Based on the crystalline symmetries, imposed by the chiral magnetic order, we argue for the presence of multiple iso-energetic Weyl nodes (nodes that are at same energy and with congruent Fermi surface around them) near chemical potential. Using the semi-classical Boltzmann equations, we show that the combined contribution to the net longitudinal magnetoconductance (LMC) and the planar Hall conductance (PHC) from tilted Weyl nodes can lead to signatures, qualitatively distinct from that of a single pair of Weyl nodes. In particular, we show that magnetic orders with different chiralities can give rise to different periods in LMC and PHC as a function of the in-plane magnetic field direction. This is ultimately related to differences in the symmetry-imposed constraints on the Weyl nodes.