First discovery that electrons move in four dimensions at the speed of light

The elusive behavior of electrons has finally been separated from everyday electronic activity in real materials. A team of physicists led by Ryuhei Oka of Ehime University has measured so-called Dirac electrons in a superconducting polymer called bis(ethylenedithio)tetrathiafulvalene. These are electrons that exist under conditions that make them virtually massless, allowing them to behave more like photons and vibrate at the speed of light. The researchers say the discovery will improve our understanding of topological materials, quantum materials that behave like electronic insulators on the inside and conductors on the outside. Superconductors, semiconductors, and topological materials are becoming increasingly important, especially with regard to potential applications in quantum computers. However, much remains unknown about these materials and their behavior. Dirac electrons refer to ordinary old electrons in unusual conditions whose quantum behavior requires knowledge of special relativity. Here, overlapping atoms place some of the electrons in strange spaces, allowing them to bounce around the material with great energy efficiency.

We now know they exist, based on theoretical physicist Paul Dirac’s equations from almost a century ago. It has been detected in graphene and other topological materials. But understanding Dirac electrons’ potential requires a deeper understanding of Dirac electrons, and this is where physicists run into a problem. Because Dirac electrons coexist with standard electrons, it is very difficult to clearly identify and measure one type. Oka and his colleagues discovered a way to accomplish this by exploiting a property called electron spin resonance. Electrons are rotating charged particles. Because of this rotating charge distribution, they each have a magnetic dipole. Therefore, when a magnetic field is applied to a material, it interacts with the spins of all unpaired electrons in that material and can change their spin state. This technique allows physicists to detect and observe unpaired electrons. And, as discovered by Oka and colleagues, it can also be used to directly observe the behavior of Dirac electrons in bis(ethylenedithio)tetrathiafulvalene and distinguish them from standard electrons as a different spin system. . The research team discovered that to fully understand Dirac electrons he needed to describe them in four dimensions. There are three standard spatial dimensions: the x, y, and z axes. And then there are the energy levels of the electrons, which represent the fourth dimension. “Since 3D band structures cannot be represented in four-dimensional space, the analysis method proposed here provides a general way to express important and easy-to-understand information about band structures that cannot be expressed using other methods.” The researchers explain in their paper. ” receive.” By analyzing Dirac electrons using these dimensions, researchers were able to discover things we didn’t know before. Your movement speed is not constant. Rather, it depends on the temperature and the angle of the magnetic field within the material. This means we now have another piece of the puzzle that helps us understand the behavior of Dirac electrons. This could help exploit its properties in future technologies.

source: https://pubs.rsc.org/en/content/articlelanding/2024/ma/d3ma00619k