Thermopower and magnetic torque reveal multiple electron orbits in PtBi₂
PtBi₂ crystals showed a large magnetoresistance at low temperature. Two independent measurements picked up several sets of quantum oscillations.
At 1.8 K and 9 T, the magnetoresistance of a PtBi₂ crystal reached 515,000% and was still rising. To track how electrons moved in the field, the team measured both the voltage induced by a temperature difference and the torque on the crystal.
Both signals oscillated as the field changed. The researchers resolved frequencies from 62.5 to 1476 T, evidence for multiple pockets of the Fermi surface. Liyuan Zhang at SUSTech is the corresponding author of the Applied Physics Letters paper.