skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Scanning tunneling microscopy of atoms and charge density waves in 1T-TaS/sub 2/, 1T-TaSe/sub 2/ and 1T-VSe/sub 2/

Abstract

The layer structure dichalcogenide materials TaS/sub 2/ and TaSe/sub 2/ grow in several different phases depending on the coordination between the Ta and chalcogenide atoms and the number of three layer sandwiches per unit cell. The 1T phase has octahedral coordination between the Ta and chalcogenide atoms and has one three layer sandwich per unit cell. The high temperature Fermi surfaces (FSs) of the 1T phase Ta based materials exhibit a favorable nesting condition and undergo a charge-density-wave (CDW) transition at temperatures well above room temperature. At low temperatures the CDWs form a ..sqrt..13 /ovr string/a /times/ ..sqrt..13 a commensurate superlattice. STM scans on the 1T phases confirm the presence of an extremely strong CDW modulation inducing z-deflections in the constant current mode of anomalously large values. 1T-VSe/sub 2/ is also a member of the VB layer structure dichalcogenide group and band structure calculations show the high temperatures FS to be similar to that of 1T-TaSe/sub 2/. However, sufficient differences exist such that the CDW formation is quite different. The CDW superlattice is observed to form only below room temperature and locks into a 4/ovr string/a /times/ 4/ovr string/a superlattice below /approximately/80K rather than the ..sqrt..13 /ovr string/a /times/ ..sqrt..13more » /ovr string/a one observed in 1T-TaSe/sub 2/. Based on electron and neutron diffraction results on stoichiometric 1T-VSe/sub 2/ two phase transitions are detected, a second order transition at 110K and a first order transition at /approximately/80K. 20 figs.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Virginia Univ., Charlottesville (USA). Dept. of Physics
OSTI Identifier:
6933485
Report Number(s):
DOE/ER/45072-33
ON: DE89003001
DOE Contract Number:  
FG05-84ER45072
Resource Type:
Technical Report
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; TANTALUM SELENIDES; CRYSTAL STRUCTURE; TANTALUM SULFIDES; CRYSTAL DEFECTS; CRYSTALS; PHASE TRANSFORMATIONS; SCANNING ELECTRON MICROSCOPY; CHALCOGENIDES; ELECTRON MICROSCOPY; MICROSCOPY; REFRACTORY METAL COMPOUNDS; SELENIDES; SELENIUM COMPOUNDS; SULFIDES; SULFUR COMPOUNDS; TANTALUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; 656003* - Condensed Matter Physics- Interactions between Beams & Condensed Matter- (1987-); 360102 - Metals & Alloys- Structure & Phase Studies

Citation Formats

Slough, G, Giambattista, B, Johnson, A, McNairy, W W, and Coleman, R V. Scanning tunneling microscopy of atoms and charge density waves in 1T-TaS/sub 2/, 1T-TaSe/sub 2/ and 1T-VSe/sub 2/. United States: N. p., 1988. Web.
Slough, G, Giambattista, B, Johnson, A, McNairy, W W, & Coleman, R V. Scanning tunneling microscopy of atoms and charge density waves in 1T-TaS/sub 2/, 1T-TaSe/sub 2/ and 1T-VSe/sub 2/. United States.
Slough, G, Giambattista, B, Johnson, A, McNairy, W W, and Coleman, R V. Fri . "Scanning tunneling microscopy of atoms and charge density waves in 1T-TaS/sub 2/, 1T-TaSe/sub 2/ and 1T-VSe/sub 2/". United States.
@article{osti_6933485,
title = {Scanning tunneling microscopy of atoms and charge density waves in 1T-TaS/sub 2/, 1T-TaSe/sub 2/ and 1T-VSe/sub 2/},
author = {Slough, G and Giambattista, B and Johnson, A and McNairy, W W and Coleman, R V},
abstractNote = {The layer structure dichalcogenide materials TaS/sub 2/ and TaSe/sub 2/ grow in several different phases depending on the coordination between the Ta and chalcogenide atoms and the number of three layer sandwiches per unit cell. The 1T phase has octahedral coordination between the Ta and chalcogenide atoms and has one three layer sandwich per unit cell. The high temperature Fermi surfaces (FSs) of the 1T phase Ta based materials exhibit a favorable nesting condition and undergo a charge-density-wave (CDW) transition at temperatures well above room temperature. At low temperatures the CDWs form a ..sqrt..13 /ovr string/a /times/ ..sqrt..13 a commensurate superlattice. STM scans on the 1T phases confirm the presence of an extremely strong CDW modulation inducing z-deflections in the constant current mode of anomalously large values. 1T-VSe/sub 2/ is also a member of the VB layer structure dichalcogenide group and band structure calculations show the high temperatures FS to be similar to that of 1T-TaSe/sub 2/. However, sufficient differences exist such that the CDW formation is quite different. The CDW superlattice is observed to form only below room temperature and locks into a 4/ovr string/a /times/ 4/ovr string/a superlattice below /approximately/80K rather than the ..sqrt..13 /ovr string/a /times/ ..sqrt..13 /ovr string/a one observed in 1T-TaSe/sub 2/. Based on electron and neutron diffraction results on stoichiometric 1T-VSe/sub 2/ two phase transitions are detected, a second order transition at 110K and a first order transition at /approximately/80K. 20 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1988},
month = {1}
}

Technical Report:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that may hold this item. Keep in mind that many technical reports are not cataloged in WorldCat.

Save / Share: