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Atomic force microscopy of charge density waves and atoms on 1T-TaSe sub 2 , 1T-TaS sub 2 , 1T-TiSe sub 2 , and 2H-NbSe sub 2

Journal Article · · Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States)
OSTI ID:5227428
; ;  [1];  [2]
  1. Univ. of California, Santa Barbara (United States)
  2. Univ. of Virginia, Charlottesville (United States)

In this paper, atomic force microscopy (AFM) measurements on TaSe{sub 2} and 1T-TaS{sub 2} will be presented clearly resolving both the atoms with a z deflection of {approx} 0.5 {angstrom}. All of the measurements have been carried out at room temperature using freshly cleaved crystals in air. It has been possible to distinguish very clearly between the commensurate CDW structure on 1T-TaSe{sub 2} and the incommensurate CDW structure on 1T-TaS{sub 2}. For the commensurate CDW structure on 1T-TaSe{sub 2}, the rotation angle between the atomic lattice and the CDW superlattice is measured as 14.2{degree} {plus minus} 0.5. For the incommensurate CDW structure on 1T-TaS{sub 2}, the rotation angle between the atomic lattice and the CDW superlattice is measured as 12.1{degree} {plus minus} 0.3. A detailed analysis of the Fourier transformation suggest no appreciable regions of commensurate CDWs at an angle of 13.9{degree}. Instead, the analysis favors a continuous modulation of the CDW amplitude, in agreement with recent STM data. The mechanism involved in the AFM response to the CDW structure and the magnitude of the z deflection will be discussed. In addition, high resolution AFM scans of atoms on 1T-TiSe{sub 2} and 2H-NbSe{sub 2} are presented that have no CDWs at room temperature.

DOE Contract Number:
FG05-84ER45072
OSTI ID:
5227428
Journal Information:
Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States), Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States) Vol. 9:2; ISSN 0734-211X; ISSN JVTBD
Country of Publication:
United States
Language:
English