Thesis High-Resolution Photoemission Study of Kondo Insulators ...
Thesis High-Resolution Photoemission Study of Kondo Insulators ...
Thesis High-Resolution Photoemission Study of Kondo Insulators ...
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70 Chapter 5. Temperature Dependence <strong>of</strong> the <strong>High</strong>-<strong>Resolution</strong> <strong>Photoemission</strong> ...<br />
states has been shown to affect the conduction-band states over a wide (∼ 40 meV)<br />
energy range in the study <strong>of</strong> Yb1−xLuxB12 [5.6]<br />
Intensity<br />
DOS<br />
YbB 12<br />
hν = 21.2 eV<br />
305 K<br />
225 K<br />
150 K<br />
75 K<br />
6 K<br />
305 K<br />
225 K<br />
150 K<br />
75 K<br />
6 K<br />
-150 -100 -50 0 50 100<br />
Energy relative to E F (meV)<br />
Figure 5.4: Top: <strong>High</strong>-resolution photoemission spectra <strong>of</strong> YbB12 near EF (hν = 21.2<br />
eV). Bottom: Spectral DOS at each temperature (thick curve) together with the DOS<br />
at 305 K (thin curve). The bottom line is the zero for the DOS at 6 K and the other<br />
densities <strong>of</strong> states have been <strong>of</strong>fset.<br />
Recently, Breuer et al. [5.22] reported the non-f photoemission spectra <strong>of</strong> another<br />
<strong>Kondo</strong> insulator Ce3Bi4Pt3 (Tmax ∼ 80 K and ∆act ∼ 4 meV) in comparison with a<br />
<strong>Kondo</strong> metal CeSi2. The spectrum <strong>of</strong> Ce3Bi4Pt3 showed a shallow dip <strong>of</strong> ∼ 20 meV<br />
around EF and the spectrum <strong>of</strong> CeSi2 was identical to a simple Fermi edge. Very re-