Researchers have developed a novel method for separating electrons based on their chirality, a property related to their spin, using the unique quantum geometry of topological materials. This breakthrough, published in the journal Nature, could lead to new types of electronic devices that manipulate electron flow without the need for magnetic fields.

The team, whose affiliations were not immediately available, focused on a material called palladium gallium (PdGa), a topological semimetal. These materials possess unique electronic band structures with points where electrons behave as if they have no mass and exhibit distinct chiralities. Traditionally, separating electrons by chirality required strong magnetic fields or magnetic doping, which can be cumbersome and limit device applications.

Instead, the researchers harnessed the quantum geometry of PdGa's electronic bands. This quantum geometry induces an "anomalous velocity" in the chiral fermions, causing them to move in different directions based on their chirality. By fabricating PdGa into a three-armed device, the team was able to spatially separate currents of electrons with opposite chiralities into the outer arms.

"This is a fundamentally new way to control electron flow," said a lead researcher in the study. "By exploiting the intrinsic quantum geometry of the material, we can achieve chirality-based separation without external magnetic fields."

The separation of chiral currents also leads to the separation of orbital magnetizations, which are related to the intrinsic angular momentum of the electrons. This opens up possibilities for creating devices that manipulate both charge and spin currents.

Topological semimetals have garnered significant attention in condensed matter physics due to their unusual electronic properties. The band crossings in these materials are protected by topology, meaning they are robust against small perturbations. This makes them promising candidates for developing new electronic devices.

The team demonstrated the separation of chiral currents by observing their quantum interference, a phenomenon that occurs when electrons behave as waves and interfere with each other. The interference patterns confirmed that electrons with opposite chiralities were indeed being separated.

The implications of this research are far-reaching. The ability to control electron flow based on chirality without magnetic fields could lead to more efficient and compact electronic devices, including sensors, spintronic devices, and quantum computing components.

Further research is needed to explore the full potential of this technology and to identify other materials with suitable quantum geometry for chiral separation. The team plans to investigate the performance of PdGa-based devices under different conditions and to explore new device architectures.