Chapter 1: Discovering Chiral Surface Excitons

Recent research has unveiled a remarkable type of electron—spiraling in a manner akin to planetary motion. This discovery holds significant promise for innovations in lighting, lasers, solar energy, and quantum computing.

Physicists from Rutgers University and other institutions have identified an exotic formation of electron pairs that exhibit a spiral motion reminiscent of planets. These pairs, termed ‘chiral-surface-excitons,’ consist of particles and their corresponding antiparticles, which are bound together and rotate around one another on solid surfaces, as reported in the Proceedings of the National Academy of Sciences.

The image illustrates two varieties of ‘chiral surface excitons,’ activated by right-handed and left-handed light (photons depicted in blue). Each exciton comprises an electron (shown in light blue) orbiting a ‘hole’ (represented in black), aligned with the light's orientation. This interaction leads to their annihilation in under a trillionth of a second, resulting in the emission of light (green photons), which can be utilized in lighting, solar cells, lasers, and display technologies (Hsiang-Hsi (Sean) Kung/Rutgers University-New Brunswick).

Hsiang-Hsi (Sean) Kung, the lead author and a graduate student at Rutgers, elucidates: “Excitons form when intense light strikes solid materials, displacing negatively charged electrons from their equilibrium positions and creating positively charged 'holes'. The electrons and holes behave like spinning tops, bound together by the attractive Coulomb force.”

These electrons progressively spiral toward the holes, resulting in their annihilation and the release of a type of light known as ‘photoluminescence’ within a trillionth of a second. By analyzing this emitted light, researchers can gain insights into the behavior of electrons and the resultant holes within a conductor's surface. This discovery carries substantial implications for technologies including solar panels, lasers, and various display systems.

Kung further emphasizes, “While excitons have been recognized in semiconductors since the late 1950s, their use in daily technologies ranges from solar cells to lasers. However, the properties of excitons in semimetals and metals remain inadequately explored.”

The researchers identified chiral excitons on the surface of a crystal known as bismuth selenide, a material that could be produced in large quantities and integrated into electronic coatings and materials at ambient temperatures.

Professor Girsh Blumberg, the senior author and a physics professor, states: “Bismuth selenide is a captivating compound that belongs to a class of quantum materials referred to as ‘topological insulators.’ These materials possess several surface channels that are highly efficient at conducting electricity.”

The fundamental structure of bismuth selenide consists of a five-layer arrangement made up of alternating single-atom sheets of selenium (orange) and bismuth (purple). This compound shows great potential in advancing quantum computing technologies.

Kung concludes: “Given its semimetallic characteristics, we believe our findings could broaden the applications of bismuth selenide in optoelectronics, which merges light and electronic functionalities.”

Chapter 2: Implications and Further Research

The first video discusses the recent Nobel Prize awarded to scientists for their groundbreaking work on electrons, providing insights into their significance in modern physics.

The second video delves into how physicists managed to capture an image of an electron, explaining the complexities and implications of the 2023 Nobel Prize in Physics.