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. This breakthrough, detailed in a recent Nature publication, utilizes the quantum geometry of topological bands in a material called Palladium Gallide (PdGa) to filter and direct electrons with opposite chiralities into distinct pathways.

The research team, whose members were not immediately available for comment, demonstrated this phenomenon by fabricating PdGa devices in a three-arm geometry. These devices exhibited a nonlinear Hall effect, a phenomenon where the electrical current is not directly proportional to the applied voltage. This effect arises from the quantum-geometry-induced anomalous velocities of chiral fermions, leading to the spatial separation of transverse chiral currents with opposite anomalous velocities into the outer arms of the device.

Chirality, in the context of electrons, refers to a "handedness," where electrons can have either a left-handed or right-handed spin orientation relative to their direction of motion. Separating electrons based on chirality has potential applications in spintronics, a field that aims to use the spin of electrons, rather than their charge, to develop new electronic devices. Traditional methods for manipulating chiral electrons often rely on strong magnetic fields or magnetic dopants, which can be energy-intensive and introduce unwanted effects.

The new method overcomes these limitations by exploiting the intrinsic quantum geometry of the electronic bands in PdGa. This quantum geometry acts as a filter, guiding electrons with different chiralities into separate channels. The separated chiral currents also carry orbital magnetizations with opposite signs, further enhancing the potential for spintronic applications.

The team observed quantum interference patterns, confirming the separation of chiral currents in the absence of any magnetic field. This observation provides direct evidence of the effectiveness of the quantum-geometry-based chiral filter.

Experts believe this discovery could pave the way for more energy-efficient and compact spintronic devices. The ability to manipulate chiral electrons without magnetic fields opens up new possibilities for developing advanced electronic components, such as spin-based transistors and memory devices.

Further research is underway to explore the potential of this technology and to identify other materials that exhibit similar quantum-geometric properties. The team is also working on optimizing the device design to improve the efficiency of chiral separation and to explore potential applications in various spintronic devices.