Researchers from the Massachusetts Institute of Technology (MIT) have successfully recreated the phenomenon of “regional states” of electrons using ultra-cold sodium atoms. This groundbreaking experiment allowed for a more detailed study of electron behavior at the edges of materials, which was previously challenging to observe due to its short duration.
Edge states occur when electrons move along material boundaries in a unidirectional manner, without resistance or energy loss. This phenomenon is related to the quantum Hall effect, where electrons, under the influence of a magnetic field, follow circular trajectories on flat surfaces. In topological materials, electrons are expected to accumulate at specific locations on the edge and move in a quantized manner. However, these processes typically last only femtoseconds, posing difficulties for observation.
To address this issue, MIT scientists utilized approximately one million sodium atoms cooled to an ultra-cold state using lasers and precisely positioned them. By applying physical forces that simulated a magnetic field, conditions were created for the emergence of edge states. A laser boundary was established around the system to mimic the material’s edge.
Upon encountering this “boundary,” sodium atoms started moving along it in a single direction without any deceleration or losses. Even with the introduction of artificial obstacles, the atoms continued to follow the edge without scattering elsewhere in the system. Physicist Martin Zwierlein likened this behavior to rapidly rotating balls in a bowl, perpetually moving along its walls without friction or losses.
This study validated theoretical predictions regarding edge states and opens up avenues for future experiments using atoms as substitutes for electrons in studying such phenomena. The findings could also contribute to the development of more efficient methods for energy transfer without losses, as well as the exploration of quantum computers and sensors.
Going forward, researchers aim to introduce additional obstacles and interactions into the system to investigate its behavior under more challenging conditions. The results of the study were recently published in the journal Nature Physics.