Researchers have developed a novel method for separating electrons based on their chirality, a property related to their spin, without the need for magnetic fields. The breakthrough, detailed in a recent Nature publication, utilizes the quantum geometry of topological bands in a material called palladium gallium (PdGa) to filter and direct electrons with opposite chiralities into distinct, spatially separated pathways.

This new approach overcomes limitations of previous methods that relied on strong magnetic fields or magnetic doping to control chiral fermionic transport, according to the study. By exploiting the inherent quantum properties of the material, the team achieved real-space separation of currents with opposite fermionic chiralities and observed their quantum interference.

The research team fabricated devices from single-crystal PdGa in a three-arm geometry. These devices exhibited quantum-geometry-induced anomalous velocities of chiral fermions, leading to a nonlinear Hall effect. The resulting transverse chiral currents, possessing opposite anomalous velocities, were spatially separated into the outer arms of the device.

"This is a fundamentally new way to control electron flow," said [Lead Researcher Name, if available, otherwise use a placeholder like "a lead researcher on the project"], "[Quote about the significance of the research, e.g., 'This opens up possibilities for developing more energy-efficient and compact electronic devices.']"

The separation of chiral currents also leads to the separation of orbital magnetizations with opposite signs, adding another dimension to the control of electron behavior.

Topological semimetals, the class of materials PdGa belongs to, host fermions with opposite chiralities at topological band crossings. These materials have garnered significant attention in condensed-matter physics due to their unique electronic properties. The ability to manipulate chiral fermions within these materials could lead to advancements in electronic and spintronic devices.

The team's findings suggest potential applications in developing new types of electronic devices that exploit the unique properties of chiral fermions. Further research will focus on optimizing the device design and exploring other materials with similar quantum geometric properties. The researchers believe this work could pave the way for more efficient and compact electronic devices that utilize the spin of electrons in addition to their charge.