Hostname: page-component-8448b6f56d-42gr6 Total loading time: 0 Render date: 2024-04-25T05:05:51.274Z Has data issue: false hasContentIssue false

High Resolution Electron Microscopy of Triply Incommensurate Phase of 2H-TaSe2

Published online by Cambridge University Press:  25 February 2011

Takashi Onozuka
Affiliation:
School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
Nobuo Otsuka
Affiliation:
School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
Hiroshi Sato
Affiliation:
School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907
Get access

Abstract

The triply incommensurate phase of 2H-TaSe2 obtained by cooling from the normal phase was investigated by TEM between 87K and 113K with the resolution of 3 A. Moire-like patterns observed in this phase were confirmed to be interference fringes due to the first and the second order diffraction beams from the incommensurate structure and were not due to the dark field diffraction contrast of domains of the commensurate structure as interpreted earlier. Lattice fringes (∼9Å) of this modulated phase do not show any discontinuity across the boundaries of regions of different contrasts of the moire-like fringes which is expected from domain boundaries. Instead, a periodic change in the spacing of the lattice fringes (phase slip region) expected from the superposition of split superlattice spots in forming the lattice image is observed. This is the first direct observation of the existence of the phase slip region which is also expected from the discommensuration theory.

Type
Articles
Copyright
Copyright © Materials Research Society 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Sato, H. and Toth, R. S., Phys. Rev. 124, 1833 (1961). 127, 469 (1962).Google Scholar
2. Sato, H. and Toth, R. S., Phys. Rev. Lett. 8, 239 (1962).Google Scholar
3. Sato, H. and Toth, R. S., in Alloying Behavior in Concentrated Solid Solutions, Edited by Massalski, T. B., Gordon and Breach Science Publishers, Inc., N.Y. (1965), p. 295419.Google Scholar
4. Sato, H. and Toth, R. S., Bull. Soc. Franc, Miner. Cryst. 91, 557 (1968).Google Scholar
5. Hirabayashi, M., Yamaguchi, S., Hiraga, K., Ino, N., Sato, H. and Toth, R. S., Proc. Third Bolton Landing Conference on Ordered Alloys: Structural Applications and Physical Metallurgy 1969, Claitor's Publishing Div., Baton Rouge (1970) pp. 137–148.Google Scholar
6. Sato, H., AlP Conference Proceedings, No. 53 (Modulated Structures) (1979), pp. 165–167.Google Scholar
7. Wilson, J. A., DiSalvo, F. J. and Mahajan, S., Advan. Phys. 24, 117 (1975).Google Scholar
8. Fung, K. K., McKernan, S., Steeds, J. W. and Wilson, J. A., J. Phys. C14, 5417 (1981).Google Scholar
9. Chen, C. H., Gibson, J. M. and Flemming, R. M., Phys. Rev. Lett. 47, 723 (1981).CrossRefGoogle Scholar
10. Chen, C. H., Gibson, J. M. and Flemming, R. M., Phys. Rev. B 326, 184 (1982).Google Scholar
11. Gibson, J. M., Chen, C. H. and McDonald, M. L., Phys. Rev. Lett. 50, 1403 (1983).Google Scholar
12. Gibson, J. M. and McDonald, M. L., Ultramicroscopy, 12, 219 (1984).CrossRefGoogle Scholar
13. Onozka, T., Otsuka, N. and Sato, H., to be published in Phys. Rev. B.Google Scholar
14. Otsuka, N. and Sato, H., J. Solid State Chemistry (accepted).Google Scholar
15. Moncton, D. E., Axe, J. D. and DiSalvo, F. J., Phys. Rev. B 16, 801 (1977).CrossRefGoogle Scholar
16. Flemming, R. M., Moncton, D. E., McWhan, D. B. and DiSalvo, F. J., Phys. Rev. Lett. 45, 576 (1980).Google Scholar
17. McMillan, W. L., Phys. Rev. B 12, 1187 (1975). 14, 1496 (1976).CrossRefGoogle Scholar
18. Nakanishi, K. and Shiba, H., J. Phys. Soc. Japan, 45, 1147 (1978).CrossRefGoogle Scholar
19. Fujino, Y., Sato, H. and Otsuka, N., the previous paper.Google Scholar