The peculiar metallic electronic states observed in the Kondo insulator, samarium hexaboride (SmB
6
), has stimulated considerable attention among those studying non-trivial electronic phenomena. However, experimental studies of these states have led to controversial conclusions mainly due to the difficulty and inhomogeneity of the SmB
6
crystal surface. Here, we show the detailed electronic structure of SmB
6
with angle-resolved photoelectron spectroscopy measurements of the three-fold (111) surface where only two inequivalent time-reversal-invariant momenta (TRIM) exist. We observe the metallic two-dimensional state was dispersed across the bulk Kondo gap. Its helical in-plane spin polarisation around the surface TRIM indicates that SmB
6
is topologically non-trivial, according to the topological classification theory for weakly correlated systems. Based on these results, we propose a simple picture of the controversial topological classification of SmB
6
.
Assessment of pain, depression, and anxiety by visual analogue scale in Japanese women with rheumatoid arthritis Visual analogue scales (VAS) of depression and anxiety were compared with standard full-length measures of these variables and with VAS of pain (VAS Pain). This was a good way to develop a practical methodology for the routine assessment of pain and affect in rheumatoid arthritis (RA) patients. The reliability of VAS Pain was studied by test-retest. The validity of VAS Pain in our sample was proved by correlations with the results of other tests. We also investigated the relationship between VAS Pain and C-reactive protein (CRP). In 145 female RA patients, VAS of depression and anxiety were significantly correlated with full-length measures of these variables, and accounted for the majority of the explained variance in VAS Pain, while the full-length standard measures contributed little more. In conclusion, VAS measurements of pain and affect were comprehensible, easily filled-out, and reliable in a sample of Japanese women with RA, and could capture some aspect of affective distress unique to RA patients.
YbB12 has been investigated energetically as a typical Kondo insulator. To study detailed formation mechanism of Kondo energy gap, we have investigated transport and magnetic properties of Yb1-xR3+xB12 (R3+ = non-magnetic trivalent ions). Recently, we have recently succeeded in substitution of Ca2+ for Yb site in YbB12 by high-pressure synthesis. In Ca- and Lu-substituted alloys both of magnetic susceptibility and specific heat C/T at low temperatures, remarkably show larger increase than those of powdered YbB12. These increases are due to giant increase of density of state in an in-gap state.
It has been recently found that Kondo insulator YbB 12 has the metallic state on the surface by transport properties and photoemission spectra etc. To study such exotic state in detail, we have investigated transport and magnetic properties of Yb 1-x R 3+ x B 12 (R 3+ = non-magnetic trivalent ions). Furthermore, we have succeeded in substitution of Ca 2+ for Yb site in YbB 12 by high-pressure synthesis. As Ca 2+ contents increase, the density of states at Fermi energy D(ε F) is expected to decrease gradually. The activation energies have been found to be almost constant in the range of 0 < x < 0.2. This result suggests that coherence of Kondo clouds in Ca-substituted alloys is maintained up to x = 0.2.
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