Anomalous electromagnetic induction induced by a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>2</mml:mn><mml:mi>π</mml:mi></mml:math> jump in Berry flux

The Berry curvature, resembling the magnetic field in reciprocal space, offers a captivating avenue for exploring unique electromagnetic phenomena devoid of real-space analogs. Here, we investigate the emergent electromagnetic induction by solenoidal Berry curvature with its field lines forming loops, links, and knots. In stark contrast to the conventional results predicted by Faraday's law, which dictates that alternating magnetic fields yield alternating electric fields with a net zero average, the alternating Berry curvature can engender directional electromagnetic induction. Such an effect is attributed to the presence of singularities in the Berry curvature, accompanied by a <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>2</a:mn><a:mi>π</a:mi></a:mrow></a:math> jump in the Berry flux. Notably, this jump does not trigger a diamagnetic impulse, due to the gauge invariance of the Berry phase modulo <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mn>2</b:mn><b:mi>π</b:mi></b:mrow></b:math>. Consequently, the induced electric field maintains finite values under time averaging, manifesting itself as a directional pumping current. Our research sheds light on a different type of anomalous electromagnetic induction effect, thereby expanding our comprehension of exotic electromagnetic phenomena.