Topological electronic transport properties of magnetic Weyl semi-metal Co₂MnGa

Full text: Topologically interesting materials that are also magnetic are expected to be particularly important for the study of novel topological phases in condensed matter. The coupling of magnetic and transport properties in such materials could allow for spin topotronic devices, that take advantage simultaneously of the magnetic and topological physics. For instance, there are claims that ferromagnetic topological materials may allow the quantum anomalous Hall effect state, normally only seen below 10 K, to persist to room temperature. Excitingly, very recent results indicate that Heusler alloy Co₂MnGa could be a room-temperature ferromagnetic Weyl semi-metal, a material with protected electronic states due to a topological band structure [1-3]. In this presentation I will show the signatures of these topological states are visible in magnetoelectric and magneto-thermoelectric measurements in thin films of Co₂MnGa. Thin films of Co₂MnGa set new room temperature records of the anomalous Hall and anomalous Nernst effects. For thinner films, the anomalous Hall effect weakens, and we discuss the implications of this for exploiting the Weyl-like characteristics of Co₂MnGa in thin film devices. (author)