Giant anomalous Hall and Nernst effects in cubic full Heusler compounds
In recent years, huge progress was made in understanding topological phases of matter and classifying them from the symmetry point of view. However, most of this work was done for time-reversal invariant, i.e non-magnetic, systems due to the challenges that arise when dealing with magnetism. Through this restriction, some important effects that are directly linked to the topological properties of the materials, are neglected. These are, among others, the electrical anomalous Hall effect (AHE) and the thermoelectrical anomalous Nernst effect (ANE).
To enhance the general understanding of these two effects as well as identifying design guidelines for high-performance compounds we recently performed a theoretical analysis of more than 250 magnetic full Heusler compounds reported in the Heusler Database of the University of Alabama. Here, we overcome the challenge of identifying the correct magnetic ground state by combining basic knowledge of the Heusler compounds with the total magnetization given in the database. Our results reveal the importance of symmetries, especially mirror planes, in combination with magnetism to find enhanced Berry curvature and thus large AHE and ANE. In addition, our material scan allows us to predict Heusler compounds that out-perform the so far reported record values for both effects.