| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2009: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2008: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2007: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Research Abstract |
We have investigated the layered nitride superconductors by means of the low-temperature ultra-high vacuum scanning tunneling microscopy/spectroscopy (STM/STS). The STM topographies at 5K clearly indicate the difference in the surface arrangements of metal atoms between α(FeOCl) and β(SmSI) layered polymorphs. The STS spectra exhibit a large difference between them. For α-K_xTiNCl, the energy gap 2Δ is very inhomogeneous down to the area of ～20nm^2, while for β-HfNCl_<0.7> they are homogeneous even up to ～100nm^2. The maximum gap ratio 2Δ/k_BT_c (k_B : Boltzmann constant, Tc : critical temperature) ～40 for α-K_xTiNCl and the uniform ratio 2Δ/k_BTc～10 for β-HfNCl_<0.7> are both larger than the BCS value 3.5, thereby indicating that the pairing mechanism is different from that of the conventional superconductors.
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