Giacomo Sala, an experimental physicist at the Paul Scherrer Institute's (PSI) Center for Neutron and Muon Science, has been awarded a European Research Council (ERC) Starting Grant worth €2.3 million (about US$2.7 million) over five years for Q-GEOMSPIN, a project aiming to experimentally connect spintronics with the emerging field of quantum geometry for the first time.
Spintronics, which exploits the intrinsic spin of electrons alongside their charge to store and process information, has existed as a field for three decades and underpinned the giant magnetoresistance effect that multiplied hard drive storage density in the 1980s. Quantum geometry, by contrast, describes the geometric structure of electron wave functions inside a solid. Sala's project focuses specifically on a subfield called the quantum metric, which he compares to how mass curves space in general relativity: just as that curvature explains the Earth's orbit around the sun, quantum metric describes a curvature of momentum space that deflects electrons as they move through a material. Theoretical work has suggested this curvature could give rise to spintronic effects that have so far gone unrecognized, a connection Sala says has not yet been tested experimentally.
With the funding, Sala will hire two doctoral candidates and a postdoctoral researcher to fabricate and measure micrometer-scale device structures, cooled to near absolute zero in a specialized cryostat that PSI is acquiring with ERC funds to generate strong magnetic fields around the samples. Passing an electric current through the cooled devices and measuring how electrons are deflected, the team will look specifically for nonlinear effects, where small changes in voltage or magnetic field produce disproportionately large changes in the measured signal, which Sala expects to carry signatures of quantum geometry. The project will study topological materials, which conduct electricity on their surface while remaining insulating inside, alongside oxide compounds and two-dimensional van der Waals materials such as graphene.
The work will draw on PSI's Quantum Matter and Materials Center, along with the Swiss Light Source (SLS) synchrotron, the newly established PICO cleanroom for microfabrication, and potentially the Swiss Spallation Neutron Source (SINQ). Sala frames Q-GEOMSPIN as fundamental research rather than a route to a specific device, but points to higher-performance spintronic memory (MRAM) and brain-inspired computer processors as examples of the kind of applications such fundamental advances could eventually enable.