Scientists from around the globe have experimentally confirmed a unique characteristic of topological materials. Using ‘3D glasses’-like technology and particle accelerators, they successfully visualized the relationship between an electron’s topology and its quantum mechanical properties, marking a significant step forward in understanding these future-focused materials.
Topological quantum materials are seen as a beacon of hope for energy-saving electronics and the high-tech of the future. A defining feature of these materials is their ability to conduct spin-polarized electrons on their surface, while remaining non-conductive inside. To put this into perspective: In spin-polarized electrons, the intrinsic angular momentum, i.e. the direction of rotation of the particles (spin), is not purely randomly aligned.
To distinguish topological materials from conventional ones, scientists used to study their surface currents. However, an electron’s topology is closely linked to its quantum mechanical wave properties and its spin. This relationship has now been demonstrated directly by means of the photoelectric effect – a phenomenon in which electrons are released from a material, such as metal, with the aid of light.
Prof. Giorgio Sangiovanni, a founding member of ct.qmat in Würzburg and one of the theoretical physicists in the project, likened this discovery to using 3D glasses to visualize the topology of electrons. As he explains: “Electrons and photons can be described quantum mechanically as both waves and particles. Therefore, electrons have a spin that we can measure thanks to the photoelectric effect.”
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