ASPIRE Workshop 2026: Quantum State Control Using Spin-Orbit Nanostructures in Semiconductor, Topological, and 2D Materials

Focus:
Topological materials, semiconductor nanowires, GeSn/-group-IV materials, superconducting hybrid devices, and 2D/van der Waals materials.

Participants:
Tohoku University, Forschungszentrum Jülich, RWTH Aachen, RIKEN, invited speakers, and ASPIRE young researchers

Workshop Rationale and Scope:
The ASPIRE project aims to observe and control novel bound states for topological and spin qubits by combining strong spin-orbit-coupled semiconductors and topological materials with superconductors. The collaboration is built on complementary strengths: high-quality crystal growth and hybrid junction fabrication at Jülich, precise spin-orbit-interaction measurements and device optimization at Tohoku University, and RF tunneling spectroscopy of Andreev and related bound states at RIKEN.

This workshop is a focused checkpoint for sharing scientific progress, aligning material and device priorities, defining near-term experimental actions, and strengthening international circulation of young researchers through direct presentations and discussion.

In addition to the established ASPIRE pillars of topological materials and semiconductor nanowires, the 2026 Jülich workshop will explicitly emphasize GeSn alloys together with 2D and van der Waals materials. As emerging CMOS-compatible quantum materials, these platforms offer gate-tunable spin-orbit coupling, spin-valley and edge-channel physics, clean proximity interfaces, and flexible heterostructures that connect spin-orbitronics, topological transport, and superconducting hybrid quantum devices.

Objectives:

• Review progress on spin-orbit nanostructures for topological and spin quantum states.
• Compare material platforms including topological insulators, semiconductor nanowires, GeSn/-group-IV systems, graphene, WTe_2, WSe₂, and other 2D materials.
• Identify how spin-orbit coupling, proximity effects, hybrid gaps, Andreev bound states, and spin-/-valley degrees of freedom connect within the ASPIRE framework.
• Provide the JST ASPIRE Program Office (program officer Prof. Kawakami) with an overview of the project status and future directions, and giving young researchers a central role in the discussion.

Young Researcher Presentation:
The core contributed sessions balance the three ASPIRE-related young-researcher groups. One additional contribution from Anna Dyrdał's group (Adam Mickiewicz, University in Poznań, Poland) is included tentatively, subject to confirmation.

Financial Support:
The workshop is primarily supported by the Japan Science and Technology Agency (JST) through the ASPIRE program. Additional support for dissemination of research results relevant to the Horizon Europe project LASTSTEP is provided through the German participation in LASTSTEP. Furthermore, financial support is provided by DFG under Germany's Excellence Strategy—Cluster of Excellence Matter and Light for Quantum Computing (ML4Q).

Organizer:
Thomas Schäpers (FZJ), Dan Buca (FZJ), Makoto Kohda (Tohoku)