• Title/Summary/Keyword: electron microscopy

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Review on Electronic Correlations and the Metal-Insulator Transition in SrRuO3

  • Pang, Subeen
    • Applied Microscopy
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    • v.47 no.3
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    • pp.187-202
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    • 2017
  • The classical electron band theory is a powerful tool to describe the electronic structures of solids. However, the band theory and corresponding density functional theory become inappropriate if a system comprises localized electrons in a scenario wherein strong electron correlations cannot be neglected. $SrRuO_3$ is one such system, and the partially localized d-band electrons exhibit some interesting behaviors such as enhanced effective mass, spectral incoherency, and oppression of ferromagnetism and itinerancy. In particular, a Metal-Insulator transition occurs when the thickness of $SrRuO_3$ approaches approximately four unit cells. In the computational studies, irrespective of the inclusion of on-site Hubbard repulsion and Hund's coupling parameters, correctly depicting the correlation effects is difficult. Because the oxygen atoms and the symmetry of octahedra are known to play important roles in the system, scrutinizing both the electronic band structure and the lattice system of $SrRuO_3$ is required to find the origin of the correlated behaviors. Transmission electron microscopy is a promising solution to this problem because of its integrated functionalities, which include atomic-resolution imaging and electron energy loss spectroscopy.

Electron Microscopy of the Intercellular Junction of Frog (Rana temporaria) Skin (개구리 피부의 세포접착부에 관한 전자 현미경적 연구)

  • Yoon, J.S.;Chang, S.H.;Choi, K.D.
    • Applied Microscopy
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    • v.1 no.1
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    • pp.19-26
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    • 1969
  • Electron microscopy on the skin of young frogs, Rana temporaria, has been carried out with particular reference to cellular attachment sites. For the first time now several technical developments allow a more detailed visualization of the fine structure within the cellular attachment sites as well as making it possible to show the ultra-structural morphology of the junctional complexes, and to demonstrate that the desmosomes are regularly distributed aroand each skin cell, especially in the S. granulosum. The relations of these findings to these of previous investigations concerning the functional, organization of the junctional complexes and to the findings in skin cancer from a cellular adhesion view point have been briefly discussed.

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