[en] In this study, we consider a quantum spin Hall (QSH) phase in both the zigzag and the armchair type of honeycomb nanoribbons with two different atoms from the viewpoint of bulk-edge correspondence. Generally, the QSH phase in honeycomb nanoribbons is determined by the topology of the bulk Hamiltonian. However, the armchair type of nanoribbons seems to become the QSH phase in a very different region compared with bulk materials. On the other hand, the zigzag type of nanoribbons seems to become the QSH phase in almost the same region as bulk materials. We study the reason why the QSH phase in nanoribbons seems to be different from that of bulk materials using the extended Kane-Mele Hamiltonian. As a result, there is a clear difference in the edge states in the QSH phase between the zigzag and the armchair type of nanoribbons. We find that the QSH phase region in nanoribbons is actually different from that of bulk materials. This is because the coherence lengths of edge wave functions of nanoribbons are extremely influenced by their edge-shapes. We can conclude that the bulk-edge correspondence does not hold for relatively narrow nanoribbons compared with their coherence lengths and that the edge shapes of nanoribbons make their coherence lengths of edge wavefunctions different, which largely influences the QSH phase. (paper)

[en] Seven beamlines are operated for macromolecular crystallography (MX) at SPring-8. The three undulator beamlines are developed for cutting edge target and four bending-magnet beamlines are developed for high throughput MX. The undulator beamline, BL41XU that provides the most brilliant beam, is dedicated to obtain high quality data even from small-size and weakly-diffracting crystals. The minimum beam size at sample position is achieved to 10 μm diameter using a pin-hole collimator. Its photon flux at wavelength λ = 1.0 A is 2.8x10¹¹ photons/sec. This small beam coupled with irradiation point scanning method is quite useful to take diffraction dataset from small crystals by suppressing the radiation damage. These advanced technologies made a number of difficult protein structure analysis possible, (i.e. Sodium-potassium ATPase). The bending-magnet beamlines BL26B1/B2 and BL38B1 provide automatic data collection exploiting the high mobility of the beam. The beamline operation software 'BSS', sample auto-changer 'SPACE' and web-based data management software 'D-Cha' have made the automatic data collection possible. The 'Mail-in data collection system' that accepts distant users samples via courier service have made users possible to collect diffraction data without visiting SPring-8. The structural genomics research is promoted by these beamlines.