Scanning Tunneling Microscopy of the Organic Conductors (TMTSF)2X(X = C1O4-, REO4-)
Abstract
Scanning tunneling microscopy(STM) images of the(001) face (ab face) of the organic conductors (TMTSF)2X(TMTSF = tetramethyltetraselenafulvalene; X = C104-, ReO4-) reflect the surface molecular corrugation and anisotropic stacking of TMTSF molecules along the 100 direction. The lattice constants of the(001) face determined from STM for(TMTSF)2ClO4 are a 7.3 +/- 0.2 b = 7.8 +/- 0.2 A, and y = 69.50 + or - 20, and for (TMTSF)2ReO4 are 7.5 +/- 0.2 A, b 8.1 +/- 0.2 and y = 70 - or + 20, in excellent agreement with the known crystal structure. Height profile analysis of the tunneling current assigned to localized TMTSF electronic states are in agreement with the angle between the(001) face and the direction of the short axis of the TMTSF molecules. The STM images also are consistent with the high degree of electronic anisotropy of (TMTSF)2CIO4, with a broad electronic state density associated with the psuedo one-dimensional TMTSF stacks and a highly localized state density associated with Se-Se contacts between stacks along the 110 direction. The results are corroborated by STM of isomorphous(TMTSF)2Rel4 which exhibits negligible tunneling current associated with the Se-Se states, in agreement with the slightly larger Se-Se interstack distances in this compound. The lack of tunneling current in the interstack region of(TMTSF)2ReO4 signifies reduced electronic interaction transverse to the stacking direction, consistent with previously reported electronic properties of(TMTSF)2ReO4. The results indicate that STM can detect subtle differences in electronic structure that are responsible for bulk electronic properties.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 25, 1992
- Accession Number
- ADA246909
Entities
People
- Henry S. White
- Michael D. Ward
- Shulong Li
Organizations
- University of Minnesota