First lab proof of Thomson effect marks major physics breakthrough

Japanese researchers have experimentally confirmed the transverse Thomson effect for the first time, validating a 174-year-old theoretical prediction in thermoelectric physics. This effect involves controlling the direction of heating and cooling flows by altering the direction of an applied magnetic field, differing fundamentally from the conventional Thomson effect. The team, led by Atsushi Takahagi and Ken-ichi Uchida, demonstrated this phenomenon using a semimetal alloy of bismuth and antimony (Bi88Sb12), chosen for its strong Nernst effect near room temperature. Their work, published in Nature Physics, revealed that unlike the conventional Thomson effect—which depends solely on the temperature derivative of the Seebeck coefficient—the transverse Thomson effect also depends on the magnitude of the Nernst coefficient, offering a new mechanism for active thermal management. The researchers overcame previous experimental challenges caused by competing thermoelectric effects (Peltier and Ettingshausen) by employing an infrared camera to isolate the thermal signals corresponding to the transverse Thomson effect.