Search Results
Near-field interference map due to a dipolar emission near the edge of a monocrystalline gold platelet
2022, Abbasirad, N., Barreda, A., Arslan, D., Steinert, M., Chen, Y.-J., Huang, J.-S., Staude, I., Setzpfandt, F., Pertsch, T.
Point source excitation and point detection in the near-field provides new perspective to study the near-field optical phenomena of plasmonic nanostructures. Using the automated dual-tip scanning near-field optical microscope (SNOM), we have measured the optical near-field response of a dipolar emission near the edge of a monocrystalline gold platelet. The image dipole method was used to analytically calculate the interference pattern due to surface plasmon polaritons excited at the position of aperture tip and those reflected from edges of the gold platelet. The near-field enhancement was observed on the edges of the gold platelet. Our results verify that automated dual-tip SNOM is an intriguing technique for quantum plasmonic studies where deterministic coupling of quantum emitters and the detection of the near-field enhancement are of great interest.
A bismuth triiodide monosheet on Bi 2 Se 3 (0001)
2019, Polyakov, A., Mohseni, K., Castro, G.R., Rubio-Zuazo, J., Zeugner, A., Isaeva, A., Chen, Y.-J., Tusche, C., Meyerheim, H.L.
A stable BiI 3 monosheet has been grown for the first time on the (0001) surface of the topological insulator Bi 2 Se 3 as confirmed by scanning tunnelling microscopy, surface X-ray diffraction, and X-ray photoemision spectroscopy. BiI 3 is deposited by molecular beam epitaxy from the crystalline BiTeI precursor that undergoes decomposition sublimation. The key fragment of the bulk BiI 3 structure, a∞2[I—Bi—I] layer of edge-sharing BiI 6 octahedra, is preserved in the ultra-thin film limit, but exhibits large atomic relaxations. The stacking sequence of the trilayers and alternations of the Bi—I distances in the monosheet are the same as in the bulk BiI 3 structure. Momentum resolved photoemission spectroscopy indicates a direct band gap of 1.2 eV. The Dirac surface state is completely destroyed and a new flat band appears in the band gap of the BiI 3 film that could be interpreted as an interface state.