Thermoelectric voltage study of 1T-TaS₂ using temperature dependent scanning tunneling spectroscopy

Using an ultra high vacuum (UHV) scanning tunneling microscope where the sample is cooled while the tip remains close to room temperature, we measured the thermoelectric voltage induced by the large thermal gradient between the tip and sample. Using tunneling thermometry technique we studied the change of electronic structures of 1 T-TaS₂ from room temperature to 40 K. At the temperature for the nearly commensurate to commensurate transition, we found an abrupt change of the thermoelectric power from a very small value to about 0.15 mV/K.