SCANNING TUNNELING SPECTROSCOPY OF 1T-TAS2 BETWEEN 300 K AND 40 K

We have used scanning tunneling spectroscopy to measure temperature de pendent tunneling spectra of 1T-TaS2 from room temperature to similar to 40 K. An abrupt transition from the charge-density-wave induced bro ad depletion to an opening of a deep pseudo gap was observed within si milar to 1 K of the nearly commensurate to commensurate transition tem perature. This pseudo gap was deep enough to form localized states at the Fermi level. Our tunneling results therefore suggest, in contrast to inverse photoelectron spectroscopy, that the band splitting of the Ta 5d band is due to the electron correlation effect.