2013 Fiscal Year Final Research Report
Surface electronic state of topological insulator : Dirac corn
| Project/Area Number |
24740204
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Condensed matter physics I
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| Research Institution | Hiroshima University |
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Principal Investigator |
ARITA Masashi 広島大学, 技術センター, 技術主任 (20379910)
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| Project Period (FY) |
2012-04-01 – 2014-03-31
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| Keywords | トポロジカル絶縁体 / 角度分解光電子分光 |
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| Research Abstract |
We have studied the electronic structure of the septuple-layer material GeBi2Te4 and quintuple-layer material Bi2Se3 which are the topological insulators by means of angle-resolved photoemission spectroscopy. We have observed a Dirac-fermion-like topological surface states around the gamma point. While the dispersion of the topological surface state in GeBi2Te4 is similar to that in Bi2Se3, the hexagonal warping effect is much stronger in GeBi2Te4. The estimated bulk band gap of GeBi2Te4 is about120 meV and the valence-band maximum is found to overlap the Dirac point. In the spectra near the Fermi level, kink structures derived from the electron-phonon interaction exists at 15-20 meV. In Bi2Se3, the electron-electron interaction decreases around Dirac point and the minimum is at Dirac point. In GeBi2Te4, that is not suppressed. That increases between bulk and surface state, because the bulk state exists around Dirac point.
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