Cornell physicists Shannon Mack and Phi Mac have created a highly controllable experimental platform for studying electrons. By stacking atom‑thick semiconductor sheets (transition‑metal dichalcogenides) they form a moiré superlattice that, when tuned with voltages, traps electrons in artificial atoms roughly 100 times larger than real atoms. Adjusting the voltage changes the number of electrons in each artificial atom, allowing the researchers to mimic different elements and to explore exotic quantum states such as Mott insulators, Wigner crystals and chiral insulators. This system provides a versatile test‑bed for probing electron interactions and could guide the design of future materials for quantum computing, energy storage and higher‑temperature superconductors.
1. Condensed matter physics studies matter and the diverse forms that arise when atoms and electrons are assembled in different ways.
2. It is described as the most active field of contemporary physics and has yielded some of the biggest breakthroughs of the past century.
3. Scientists have only scratched the surface of electrons’ potential, harnessing just a few of its behaviors.
4. A married couple of physicists at Cornell devised a method to create artificial atoms in the laboratory.
5. This achievement opens a new era of research in condensed matter physics.
6. Electrons are the animating actors of the material world, yet their behavior remains elusive.
7. Electrons can tunnel, orbit, spin, and exhibit other mysterious behaviors.
8. These properties make electrons notoriously difficult to study, especially in large groups.
9. To understand and manipulate the dynamics of many electrons together, the researchers adopted a more controllable approach in their Cornell lab.
10. They aim to explore the quantum nature of electrons using controllable experimental conditions.
11. After a decade of steady work, Shan and Mack developed an experimental setup that is novel.
12. One way to simplify experimental conditions is to employ two‑dimensional (2D) materials—sheets of metal only a few atoms thick.
13. 2D materials provide an excellent platform for controlling and understanding electron behavior.
14. Because we are three‑dimensional, 2D sheets can be viewed from above and probed with electric or magnetic fields.
15. A widely used 2D material is graphene, the building block of graphite and the thinnest material known to scientists.
16. Graphene conducts electricity with minimal resistance, but its conductivity is hard to switch off once a current flows.
17. Seeking greater control, the researchers turned to alternative 2D materials known as semiconductors.
18. In semiconductor systems the number of electrons can be tuned precisely, allowing the current to be turned off and transistors to be made.
19. They identified a semiconductor that is only a few atoms thick.
20. The researchers isolated sheets of semiconducting metals called transition‑metal dichalcogenides (TMDs), each a few atoms thick.
21. By stacking these metal flakes, slight structural differences produce a repeating moiré superlattice pattern.
22. Using their tightly controlled stack of semiconductor sheets, they explored various exotic quantum phenomena.
23. The resulting material exhibits textbook physics together with unexpected surprises in a single system.
24. They demonstrated the ability to simulate the behavior of artificial atoms by harnessing electromagnetic attraction between overlaid sheets.
25. The simulated atoms are about 100 times larger than real atoms, providing far greater experimental control.
26. Adjusting a voltage knob lets the researchers probe the system with a laser and modify the properties of the artificial atoms.
27. Changing the number of electrons in each artificial atom alters its chemistry: one electron yields an artificial hydrogen atom, two electrons an artificial helium, three electrons an artificial lithium, and so on.
28. By controlling voltage, they control electron filling in each artificial atom, enabling them to design chemistry or artificial materials simply by stacking and applying voltages.
29. Using their moiré system, the researchers coaxed electrons into unusual states of matter, including Mott insulators, Wigner crystals, and Chern insulators.
30. These states have potential applications in quantum computing, energy storage, and other next‑generation technologies.
31. Insights gained from the tiny stack of semiconductor flakes may one day reveal secrets that could power a future era of superconductors.
32. The semiconductor materials themselves may not possess a high enough critical temperature for near‑term superconducting use.
33. Nevertheless, the principles learned from them could help understand and design superconductors with higher transition temperatures.
34. Transmitting electricity over long distances without dissipation would have a major technological impact on energy infrastructure.