Anomalous thermal effect in ZrTe5 observed via photothermal measurements

In this study, we explore the magnetothermoelectric power (MTP) of ZrTe₅, a canonical Dirac semimetal, through a photothermal technique. Unlike conventional thermoelectric studies that rely on on-chip heaters and are limited by fabrication processes, especially for stress-sensitive materials, our approach utilizes photothermal effects to induce temperature gradients. Our experiments, applying a magnetic field approximately parallel and transverse to the photocurrent detection direction, reveal that the photothermal method efficiently and reliably extracts both diagonal and off-diagonal components of the thermoelectric coefficient of ZrTe₅. We observe that the longitudinal MTP reproduces features previously reported in thermal transport studies, while the photoinduced transverse MTP confirms the anomalous Nernst effect. This photothermal measurement technique opens avenues for investigating transport properties in a wide range of quantum materials, in both three-dimensional and two-dimensional systems.