Scientists have directly observed the suppression of superconductivity by an electric field, a phenomenon theoretically predicted but challenging to verify experimentally. Using a high-resolution scanning SQUID (Superconducting Quantum Interference Device) microscope, the team mapped the local magnetic response of a niobium (Nb) superconductor while applying a gate voltage. This breakthrough allows for a deeper understanding of how electric fields can modulate the quantum properties of materials.

The Meissner effect, the expulsion of magnetic fields by a superconductor, is a key signature of this quantum state. By applying a gate voltage, researchers observed a gradual reduction in the Meissner screening current at the niobium surface, indicating a localized suppression of superconductivity. This technique offers a non-invasive way to study the interface between a dielectric and a superconductor, opening new avenues for controlling superconducting properties at the nanoscale.

The ability to control superconductivity with an electric field is of great interest for the development of quantum and low-energy electronic devices. Traditionally, superconductivity has been controlled by magnetic fields or temperature changes. Electric field modulation, being more energy-efficient and compatible with modern microelectronics, could lead to the creation of superconducting transistors and other components for quantum computing and next-generation electronics. This work lays the groundwork for exploring the electrical manipulation of other quantum phenomena in materials.