Anomolous transport above the magnetic transition temperature of magnetic Weyl Semimetal CeAlGe

Magnetic Weyl semimetals—in which time reversal symmetry is broken—present an opportunity to control band topology with external parameters such as temperature and magnetic field. CeAlGe lacks inversion symmetry and becomes magnetically ordered below 4.5K, serving as an ideal material to explore the interactions of magnetism and electronic band topology. We report on anomalous electronic and thermal transport behavior in CeAlGe above the magnetic transition temperature. In particular, we find that the magnetoresistance (MR) is zero at 12.8K whereas the thermal conductivity is greatly suppressed by magnetic field at this temperature. The thermal transport and electronic transport phase diagrams suggest that this intermediate temperature region just above the magnetic transition temperature has distinct properties from the high temperature and magnetically ordered phases. We propose a mechanism for this new phase arising from the interaction between the Weyl fermions and fluctuating magnetic moments.