A team of international physicists has successfully engineered a quantum sensor with the ability to perceive minute magnetic fields on the scale of a single atom. The breakthrough represents a significant leap forward in nanotechnology and quantum measurement, providing a tool that functions much like a magnetic resonance imaging (MRI) machine for the atomic world. This development overcomes previous limitations that hindered the simultaneous measurement of both electric and magnetic fields at such a high resolution.
The new device allows scientists to explore and understand materials at their most fundamental level, promising to accelerate research in areas from materials science to quantum computing. By employing a novel design that uses a single molecule as its core component, the sensor can be positioned with extreme precision, enabling it to map the magnetic properties of individual atoms and the intricate structures they form. This capability was previously considered unattainable, and its realization opens a new window into the quantum mechanical phenomena that govern the behavior of matter at the atomic lattice scale.
A Novel Molecular-Based Approach
The success of the sensor is rooted in its unique design, which fundamentally differs from that of its predecessors. Conventional quantum sensors typically rely on imperfections within a crystal lattice, such as nitrogen-vacancy centers in diamonds. While effective, these defect-based sensors have an inherent limitation: the sensing defect must be embedded deep within the crystal for stability. This placement creates a significant distance between the sensor and the atomic-scale processes it is intended to measure, preventing it from achieving the resolution needed to see individual atoms clearly.
To overcome this challenge, the research team developed an entirely new method. Their sensor uses a single, carefully chosen molecule attached to the metallic tip of a scanning tunneling microscope (STM). An STM is a powerful instrument capable of imaging surfaces at the atomic level by scanning a sharp tip over a material. By functionalizing this tip with a sensor molecule, the team combined the precise positioning capabilities of the STM with the quantum sensitivity of the molecule. This allows the sensor to be brought within nanometers of the target material, enabling direct observation of atomic-scale magnetic fields.
Achieving Unprecedented Resolution
The ability to resolve both electric and magnetic fields with atomic precision was long thought to be an insurmountable challenge in quantum sensing. Many existing technologies could measure one or the other but struggled to capture both simultaneously at this fine scale. The newly developed molecular sensor solves this problem, setting a new standard for spatial resolution in the field. The result is a tool that can generate images of materials with a richness and detail comparable to an MRI scan, but on a vastly smaller scale.
This high-resolution imaging provides scientists with the ability to not only detect the presence of magnetic fields but also to map their shape and strength around individual atoms. Such detailed information is crucial for understanding the properties of quantum materials, where interactions between the spins of electrons give rise to exotic phenomena like superconductivity and complex forms of magnetism. The sensor can effectively visualize the subtle interplay of forces that define a material’s behavior, offering insights that were previously only available through theoretical models.
International Collaboration and Expertise
This scientific achievement was the result of a collaboration between researchers at Germany’s Forschungszentrum Jülich and the IBS Center for Quantum Nanoscience (QNS) in South Korea. The partnership leveraged the distinct strengths of each institution. The team at Jülich contributed its expertise in the bottom-up fabrication of single-molecule devices, a highly specialized skill required to construct the sensor’s core component. This involves precisely assembling molecular structures atom by atom.
The experimental work and measurements were conducted at QNS, which possesses leading-edge instrumentation and deep methodological knowledge in the field of quantum nanoscience. By combining their complementary skills, the joint team was able to build and operate the device successfully. In a statement, lead author Taner Esat of Forschungszentrum Jülich described the quantum sensor as a “game changer” for its ability to combine MRI-like richness with unparalleled spatial resolution, allowing for a deeper exploration of materials. The findings were formally documented and published in the peer-reviewed journal Nature Nanotechnology.
Implications for Future Research
The development of this atomic-scale quantum sensor marks a significant milestone in quantum technology and is expected to have far-reaching effects across numerous scientific disciplines. Its immediate application will be in the field of materials science, where it can be used to investigate the magnetic properties of novel two-dimensional materials, single-atom magnets, and other quantum systems. Understanding these properties is a critical step toward designing and building next-generation electronic devices and data storage solutions.
Beyond materials science, the technology could also advance the development of quantum computers. Many proposed quantum computing architectures rely on controlling the quantum states of individual atoms or molecules. The new sensor provides a powerful tool for characterizing and troubleshooting these delicate systems. As the technology matures, it could become an indispensable instrument in physics laboratories around the world, enabling a wide range of experiments that probe the fundamental nature of magnetism, electricity, and the quantum mechanics that connect them.