Physicists have long devised creative methods to study how electrons interact within materials. These interactions are crucial because they drive important phenomena like superconductivity. However, in most materials, electron interactions are extremely weak, making them difficult to observe. One common approach to amplifying these interactions involves reducing the electrons’ motional energy. Scientists achieve this by artificially creating a crystal lattice with a large lattice constant — meaning the distance between lattice sites is increased. While the interaction energy remains small, it becomes relatively more significant, making interaction effects easier to detect.
Traditionally, researchers have used moiré materials for this purpose. These materials, created by stacking and slightly twisting two atom-thin layers, form a superlattice that influences electron behavior. However, moiré materials also alter other physical properties, complicating studies of electron interactions.
A research team led by Ataç Imamoğlu at the Institute for Quantum Electronics at ETH Zurich has now developed a novel method to overcome this challenge. Instead of directly studying electrons within moiré materials, they use these materials to generate a spatially periodic electric field at a distance, affecting only the electrons in a separate semiconductor layer.
This new technique, recently published in Physical Review X, allows scientists to isolate and study electron interactions with greater precision, opening new possibilities for research in different materials.
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