Heinz Schmid, Hans Biebuyck, et al.
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
In order to gain some insight into the nature of the interactions in TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane), we compare the magnitude of the observed magnetic susceptibility χ with the predictions of two simple models. First we consider a tight-binding band of noninteracting electrons and find that the magnitude of the observed high-temperature χ is large compared to that calculated using the expected bandwidth. The same conclusion is also reached by a more general consideration of the magnitude of the product Tχ. It is concluded that at high temperatures χ is enhanced. We then compare the observed χ to calculations using a Hubbard model with on-site Coulomb repulsion energy U. χ is calculated in both the low-U and large-U limits and, in either limit, the large magnitude of χ can be readily accounted for. Using these two results, a relationship between the two parameters U and the bandwidth 4 t is obtained, knowing the magnitude of χ at 300 K. From independent estimates of 4 t, it is concluded that U is comparable or larger than 4 t, at least on one stack. Additional evidence for and against the presence of Coulomb interactions in TTF-TCNQ is summarized. © 1977 The American Physical Society.
Heinz Schmid, Hans Biebuyck, et al.
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
E. Babich, J. Paraszczak, et al.
Microelectronic Engineering
Frank R. Libsch, Takatoshi Tsujimura
Active Matrix Liquid Crystal Displays Technology and Applications 1997
William G. Van der Sluys, Alfred P. Sattelberger, et al.
Polyhedron