Site-specified tunneling spectroscopy on commensurate 1T-TaS2

Reproducible tunneling spectra were observed using site-specified tunneling spectroscopy in commensurate 1T-TaS2, which indicated the opening of the Mott localization gap. The gap size in both sides of the Fermi level was about 400∼500 mV at 77K. Clear spatial variations of the local density of states near the Fermi level have also been observed in a reproducible manner. The tunneling spectra changed periodically as a function of position on the surface with well defined gap structures. The spatial variations of local density of states were explained by the charge transfer from charge density wave trough to crest. This charge transfer strongly supported the electron localization on the charge density wave crest by Mott localization.