Record-high Anomalous Ettingshausen effect in a micron-sized magnetic Weyl semimetal on-chip cooler

Solid-state cooling devices offer compact, quiet, reliable and environmentally friendly solutions that currently rely primarily on the thermoelectric (TE) effect. Despite more than two centuries of research, classical thermoelectric coolers suffer from low efficiency which hampers wider application. In this study, the less researched Anomalous Ettingshausen effect (AEE), a transverse thermoelectric phenomenon, is presented as a new approach for on-chip cooling. This effect can be boosted in materials with non-trivial band topologies as demonstrated in the Heusler alloy Co_2MnGa. Enabled by the high quality of our material, in situ scanning thermal microscopy experiments reveal a record-breaking anomalous Ettingshausen coefficient of -2.1 mV in μm-sized on-chip cooling devices at room temperature. A significant 44% of the effect is contributed by the intrinsic topological properties, in particular the Berry curvature of Co_2MnGa, emphasising the unique potential of magnetic Weyl semimetals for high-performance spot cooling in nanostructures.