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, detailed in a recent Nature publication, allows for the spatial separation of currents with opposite chiralities without the need for magnetic fields, potentially revolutionizing electronic device design.

The team, whose members are affiliated with multiple institutions, demonstrated this phenomenon using devices made from single-crystal palladium gallium (PdGa) in a three-arm geometry. They observed that the quantum geometry of the material's electronic bands induced anomalous velocities in chiral fermions, leading to a nonlinear Hall effect. This effect spatially separates transverse chiral currents with opposing anomalous velocities into the outer arms of the device.

"This is a completely new way to manipulate electrons," said [Lead Researcher Name], a [Researcher Title] at [Institution Name]. "By exploiting the intrinsic quantum geometry of the material, we can filter electrons by their chirality, opening up possibilities for new types of electronic devices."

Topological semimetals, the class of materials used in the study, host fermions with opposite chiralities at topological band crossings. Traditionally, manipulating chiral fermionic transport required strong magnetic fields or magnetic doping to suppress unwanted transport and create an imbalance in the occupancy of states with opposite Chern numbers. The new method bypasses this 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 to create more efficient and compact electronic devices. The spatial separation of chiral currents could lead to the development of new types of sensors, spintronic devices, and quantum computing components. Furthermore, the absence of a need for magnetic fields simplifies device fabrication and reduces energy consumption.

The team's findings build upon previous research into anomalous velocities in topological materials. These velocities, induced by the quantum geometry of the electronic bands, cause electrons to move in unexpected directions when subjected to an electric field. By carefully designing the device geometry and material composition, the researchers were able to harness these anomalous velocities to separate chiral currents.

The mesoscopic phase coherence of these chiral currents in opposing Chern number states also carries orbital magnetizations with opposite signs. This adds another layer of complexity and potential functionality to the system.

Future research will focus on exploring other materials with similar quantum geometric properties and optimizing device designs for specific applications. The team also plans to investigate the potential for using this technology to create new types of quantum sensors and computing devices.