Electron Beam Lithography System

• Fachliche Zuordnung: Physik der kondensierten Materie
• Förderung: Förderung in 2015
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 281418483

• Erstellungsjahr: 2019

Zusammenfassung der Projektergebnisse

Since its installation, the Electron Beam Lithography (EBL) System has been used in the dedicated clean room of the Ando Laboratory as the main work force for nano-device fabrications. The workgroup, which now consists of more than 20 people, is performing a wide range of experimental research on topological materials, including topological insulators and topological superconductors. The availability of the in-house nano-device fabrications, which became possible thanks to the installation of the EBL System, have opened vast possibilities to address the new physics that are expected to be realized in these novel classes of materials. For example, using the EBL System we fabricate Josephson junctions on topological insulators with a 50-nm gap between the superconducting electrodes to search for Majorana fermions realized in the proximity-induced topological superconducting state; in this research line, we have fabricated one of the best-performing Josephson junction devices and were able to demonstrate that the superconductivity can actually be induced in the topological surface state even when the chemical potential is tuned to the Dirac point. This result was published in Nano Letters in 2018. Another example is our experiments on the spintronic function of the surface states of topological insulators: Using the EBL System, we have fabricated spintronic devices having 500-nm-wide ferromagnetic electrodes on the topological insulator surface; in these devices we were able to detect not only the current-induced spin polarization in the surface states but also its reversal when the bulk chemical potential of the topological insulator is changed. This observation led us to propose a new principle to realize the “spin-transistor” operation using topological insulators. This result was published in Physical Review B in 2016. Besides these works on topological-insulator-based nano-devices, the EBL System was also used for the research on graphene nanoribbons and the experiments on enhanced fluorescence from nanostructures, both in collaboration with Prof. Klas Lindfors in the Department of Chemistry.

Projektbezogene Publikationen (Auswahl)

• Switching of charge-current-induced spin polarization in the topological insulator LaFeSiH. Physical Review B, 94(7).
  Yang, Fan; Ghatak, Subhamoy; Taskin, A. A.; Segawa, Kouji; Ando, Yuichiro; Shiraishi, Masashi; Kanai, Yasushi; Matsumoto, Kazuhiko; Rosch, Achim & Ando, Yoichi
  
• Anomalous Fraunhofer Patterns in Gated Josephson Junctions Based on the Bulk-Insulating Topological Insulator BiSbTeSe2. Nano Letters, 18(8), 5124-5131.
  Ghatak, Subhamoy; Breunig, Oliver; Yang, Fan; Wang, Zhiwei; Taskin, Alexey A. & Ando, Yoichi
  
• Enhanced light–matter interaction of aligned armchair graphene nanoribbons using arrays of plasmonic nanoantennas. 2D Materials, 5(4), 045006.
  Pfeiffer, Markus; Senkovskiy, Boris V.; Haberer, Danny; Fischer, Felix R.; Yang, Fan; Meerholz, Klaus; Ando, Yoichi; Grüneis, Alexander & Lindfors, Klas
  
• Observation of Room-Temperature Photoluminescence Blinking in Armchair-Edge Graphene Nanoribbons. Nano Letters, 18(11), 7038-7044.
  Pfeiffer, Markus; Senkovskiy, Boris V.; Haberer, Danny; Fischer, Felix R.; Yang, Fan; Meerholz, Klaus; Ando, Yoichi; Grüneis, Alexander & Lindfors, Klas
  
• Large-area enhancement of far-field fluorescence intensity using planar nanostructures. APL Photonics, 4(7), 076101.
  Nyman, Markus; Shevchenko, Andriy; Shavrin, Igor; Ando, Yoichi; Lindfors, Klas & Kaivola, Matti