An international team of researchers from Forschungszentrum Jülich (Germany), Tohoku University (Japan), and École Polytechnique de Montréal (Canada) has made a significant discovery in semiconductor science by revealing the remarkable spin-related material properties of Germanium-Tin (GeSn) semiconductors.
Semiconductors control the flow of electricity that power everyday technology all around us (such as cars and computers). However, technology is progressing at such a breakneck speed that it is straining current semiconductor technologies.
"Semiconductors are approaching their physical and energy-efficiency limits in terms of speed, performance, and power consumption," says Makoto Kohda (Tohoku University). "This is a huge issue because we need semiconductors that can keep up as we shift to more demanding needs such as 5G/6G networks and the increased use of Artificial Intelligence."
To overcome these challenges, scientists are turning to new classes of semiconductors, named group IV alloys, that can deliver capabilities beyond what silicon and germanium alone can deliver. The goal is not only to maintain compatibility with the existing silicon-based technology platform, which underpins the global electronics and photonics industry, but also to introduce entirely new functionalities - from faster processing and a lower energy footprint to integration with photonic and quantum technologies.
One particularly promising frontier is spintronics, an approach that goes beyond traditional electronics by using the quantum property of the electron's intrinsic angular momentum, commonly known as spin, rather than relying solely on its electrical charge. The work published in Communication Materials (October 2, 2025), unravels the material properties of silicon-integrated GeSn alloy, underlining their low in-plane heavy hole effective mass, a large g-factor, and its anisotropy.
A hole in a semiconductor is the absence of an electron, which acts like a tiny positive charge. In quantum computing, holes are useful because they can store and process quantum information - allowing fast operations and long coherence times within existing semiconductor platforms. In particular, the team confirmed high spin splitting energy, indicating that GeSn semiconductors may have considerable advantages over conventional materials such as Si and Ge. In addition, it is a highly promising route for qubits and low-power spintronic devices. Importantly, GeSn alloys are compatible with complementary metal-oxide-semiconductors (CMOS), positioning this achievement as a critical step toward revolutionary advances in quantum information processing and next-generation electronic devices.
Beyond quantum and spintronics, GeSn also provides major advantages in integrated lasing, thermoelectric, and electronic applications. Its unique band structure enables efficient light emission, making it a strong candidate for on-chip lasers and photonics. At the same time, its favorable thermal and electronic properties open possibilities for better thermoelectric energy conversion and more efficient transistors. This versatility makes GeSn not just a material for quantum research, but a multifunctional semiconductor platform that could transform multiple industries.
"Future efforts will focus on refining the device designs, scaling down components, and exploring new applications," says Kohda, "This international collaboration further supports GeSn alloys as a game-changing semiconductor that could form the backbone of future technologies."
- Publication Details:
Title: GeSn Quantum Wells as a Platform for Spin-Resolved Hole Transport
Authors: Prateek Kaul, Jan Karthein, Jonas Buchhorn, Taizo Kawano, Taisei Usubuchi, Jun Ishihara, Nicolas Rotaru, Patrick Del Vecchio, Omar Concepcion, Zoran Ikonic, Detlev Grützmacher, Qing-Tai Zhao, Oussama Moutanabbir, Makoto Kohda, Thomas Schäpers, Dan Buca
Journal: Communications Materials
