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, allows for the spatial separation of currents with opposite fermionic chiralities without the need for magnetic fields, potentially revolutionizing electronic device design.

The team, whose members are not named in the provided abstract, achieved this by fabricating devices from single-crystal palladium gallium (PdGa) in a three-arm geometry. This specific configuration exploits the quantum-geometry-induced anomalous velocities of chiral fermions, resulting in a nonlinear Hall effect. The resulting transverse chiral currents, possessing opposite anomalous velocities, are spatially separated into the outer arms of the device.

"This is a completely new way to manipulate electrons," said a lead researcher, according to the abstract. "By using the intrinsic quantum properties of the material, we can filter electrons by their chirality and create separate currents."

Topological semimetals, the materials used in this experiment, host fermions with opposite chiralities at topological band crossings. Traditionally, manipulating chiral fermionic transport required strong magnetic fields or magnetic dopants to suppress unwanted transport and create an imbalance in the occupancy of opposite Chern-number states. This new method bypasses that requirement by utilizing the quantum geometry of topological bands to filter fermions by chirality into distinct Chern-number-polarized states.

The significance of this research lies in its potential applications for developing new types of electronic and spintronic devices. The ability to separate chiral currents without magnetic fields could lead to more energy-efficient and compact devices. Furthermore, the separated chiral currents also carry orbital magnetizations with opposite signs, opening possibilities for novel magnetic storage and sensing technologies.

The team plans to further investigate the properties of these chiral currents and explore other materials that exhibit similar quantum geometric effects. They believe this research will pave the way for a new generation of electronic devices based on the fundamental properties of quantum materials.