Unlocking Magnetism: The Power of a Single Electron in Thin Layers

Graphene marked a significant milestone in the world of materials science. In 2004, Andre Geim and Konstantin Novoselov created the first single-atom thick layer of carbon, unknowingly paving the way for a new field of research. Prior to this breakthrough, ultra-thin layers just a few atoms thick, known as two-dimensional crystalline materials, had already exhibited remarkable optical, electronic, magnetic, and superconducting properties. Among the global leaders in this area of research is Thorsten Schmitt's team.

The Spectroscopy of Quantum Materials group at the PSI Center for Photon Science focuses on producing and investigating thin atomic layers composed of various chemical compounds. These layers are stacked alternately, resembling a sandwich structure. The researchers continuously uncover intriguing phenomena within these hybrid materials. Recently, they made a fascinating discovery in a superlattice composed of alternating layers of lanthanum nickelate (LaNiO3) and lanthanum titanate (LaTiO3). Lanthanum nickelate is paramagnetic, while lanthanum titanate is antiferromagnetic. When these two materials are stacked together, electrons transfer from the titanate to the nickelate, resulting in a change in magnetism: lanthanum nickelate becomes antiferromagnetic, and lanthanum titanate loses its magnetic properties.

The exchange of electrons between the lanthanum nickelate and lanthanum titanate may seem like a simple manipulation to an outsider, but for physicists, it represents a significant advancement. This tailored approach to materials opens up possibilities for innovative applications, such as future magnetic memories. Lanthanum titanate, being an insulator, is not ideal for this purpose due to its inability to conduct electricity. On the other hand, lanthanum nickelate, with its conductivity and newly acquired magnetic property, holds promise as a foundational material for spintronic computers. These computers utilize antiferromagnetic memory cells based on electron spins, replacing traditional ferromagnetic hard drives.

While Thorsten Schmitt's team is not directly focused on developing magnetic memories, their research is geared towards understanding the fundamental properties that underpin future applications. By delving into basic research, they aim to unravel the mysteries surrounding two-dimensional materials and make groundbreaking discoveries. The realm of two-dimensional materials is still rife with unexplored phenomena, driving researchers to push the boundaries of knowledge and innovation.

For more insights into the fascinating world of two-dimensional materials and the potential they hold for future technologies, stay tuned for the latest updates from the Spectroscopy of Quantum Materials group at the PSI Center for Photon Science. The journey of discovery continues as scientists delve deeper into the intricate properties of these materials, unlocking new possibilities and shaping the future of materials science and technology.