The influence of intrinsic defects of 1T-TaS_(2)on charge density waves(CDWs)is studied using scanning tunneling microscopy and spectroscopy(STM,STS),angle-resolved photoelectron spectroscopy(ARPES),and density functi...The influence of intrinsic defects of 1T-TaS_(2)on charge density waves(CDWs)is studied using scanning tunneling microscopy and spectroscopy(STM,STS),angle-resolved photoelectron spectroscopy(ARPES),and density functional theory(DFT).We identify several types of structural defects and find that most have a local character limited to a single CDW site,with a single exception which effectively behaves as a dopant,leading to band-bending and affecting multiple neighboring sites.While only one type of defect can be observed by STM topographic imaging,all defects are easily resolved in STS mapping.Our results indicate modulation of the Mott band gap commensurate with the CDW and breaking of the three-fold symmetry of electronic states.DFT calculations(with included Coulomb interactions)are used to investigate the electronic structure,focusing on both sulfur vacancy and oxygen-sulfur substitution.The sulfur vacancy system,characterized with a metallic behavior,is identified as the origin of one of the experimentally observed defects.Additionally,the effect of oxidation of 1T-TaS_(2)depends on the substitution site,leading to the heterogeneity of electronic properties.展开更多
基金supported by the National Science Centre,Poland under grants 2015/19/B/ST3/03142 and 2019/32/T/ST3/00487M.L.S.thanks for University of Lodz support under IDUB 6/JRR/2021 project.T.-C.C acknowledges support of the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Division of Materials Science and Engineering,under Grant No.DE-FG02-07ER46383+4 种基金M.G.acknowledges financial support provided by Slovak Research and Development Agency provided under Contract No.APVV-SKCZ-RD-21-0114by the Ministry of Education,Science,Research and Sport of the Slovak Republic provided under Grant No.VEGA 1/0105/20Slovak Academy of Sciences project IMPULZ IM-2021-42project FLAG ERA JTC 20212DSOTECHAuthor acknowledges the provision of the Polish Ministry of Education and Science project(Support for research and development with the use of research infrastructure of the National Synchrotron Radiation Centre SOLARIS”under contract nr 1/SOL/2021/2).
文摘The influence of intrinsic defects of 1T-TaS_(2)on charge density waves(CDWs)is studied using scanning tunneling microscopy and spectroscopy(STM,STS),angle-resolved photoelectron spectroscopy(ARPES),and density functional theory(DFT).We identify several types of structural defects and find that most have a local character limited to a single CDW site,with a single exception which effectively behaves as a dopant,leading to band-bending and affecting multiple neighboring sites.While only one type of defect can be observed by STM topographic imaging,all defects are easily resolved in STS mapping.Our results indicate modulation of the Mott band gap commensurate with the CDW and breaking of the three-fold symmetry of electronic states.DFT calculations(with included Coulomb interactions)are used to investigate the electronic structure,focusing on both sulfur vacancy and oxygen-sulfur substitution.The sulfur vacancy system,characterized with a metallic behavior,is identified as the origin of one of the experimentally observed defects.Additionally,the effect of oxidation of 1T-TaS_(2)depends on the substitution site,leading to the heterogeneity of electronic properties.
