By shedding light on electron interactions in Dirac materials, like graphene, a new discovery solves a long-standing mystery and could contribute to the development of faster electronics.
Although electrons are the basis of modern electronics and are equally crucial to the development of quantum materials and quantum computing, scientists still don’t know much about electron-electron interactions.
At low temperatures, a Fermi liquid is a quantum state of matter where electrons start flowing like a liquid, allowing a material to conduct electricity.
Coulomb’s law, on the other hand, calculates the forces by which two electrically charged particles attract or repel each other, and suggest the existence of a threshold beyond which electrons stand still and the conductivity flow is broken.
However, this phenomenon has never been scientifically experimented in Dirac materials, a class of 2D materials that include superconductors, topological insulators, and graphene.
After remaining a subject of mathematical debate for over six decades, theoretical physicists at Yale-NUS College in Singapore are providing new clues about electron-electron interactions.
The Yale-NUS team, led by Associate Professor Shaffique Adam, proposes a model to describe electron interaction in Dirac materials, beyond the Coulomb threshold.
Researchers developed a method that allows them to study “the evolution of physical observables in a controllable manner and used it to address the competing effects of short-range and long-range parts in models of the Coulomb interaction. The researchers discovered that the velocity of electrons (the “flow” speed) in a material could decrease if the short-range interaction that favoured the insulating, “frozen” state dominated. However, the velocity of electrons could be enhanced by the long-range component that favoured the conducting, “liquid” state.”
This new computer model can serve as a tool for scientists to predict long-range electron-electron interactions in Dirac materials and see how electrons switch from the conductive to insulating phase, “paving the way for developing advanced electronics such as faster processors.”
The paper, “The role of electron-electron interactions in two-dimensional Dirac fermions”, is published in Science.