Evrim Yazgin
Cosmos science journalist
For the first time, physicists have developed a quantum sensor capable of detecting magnetic fields at the scale of atoms.
Atoms range in diameter from 0.1–0.5 nanometres. That’s about one ten-billionth of a metre, or roughly a millionth the width of a human hair. At this scale, the strange effects of quantum mechanics dominate, making it difficult to visualise and precisely measure physical quantities such as electric and magnetic fields.
Quantum sensors aim to use the same quantum phenomena – such as the spin of subatomic particles or quantum entanglement – to make precise measurements.
Several quantum sensors have been developed in recent years, but atomic-scale resolution was previously thought to be unattainable for both electric and magnetic fields at the same time.
That has now changed with a new quantum sensor developed by an international team of researchers. Their design is detailed in a paper published in Nature Nanotechnology today.
Usually, quantum sensors rely on imperfections in crystal lattices. But because these defects need to be embedded deep within the crystal structure, the are often far away from the processes they are measuring.
This technology employs a new method using a single molecule.
The molecule is attached to the tip of a scanning tunnelling microscope, allowing it to be brought to within nanometres of the object being observed.
“This quantum sensor is a game changer, because it provides images of materials as rich as an MRI and at the same time sets a new standard for spatial resolution in quantum sensors,” says lead author Taner Esat from the Forschungszentrum Jülich research institute in Germany. “This will allow us to explore and understand materials at their most fundamental level.”
Another advantage of the new sensor is that it can be constructed and implemented in existing laboratories around the world.
“Preceding techniques for visualizing materials use large, bulky probes to try to analyze tiny atomic features,” adds fellow lead author Dimitry Borodin from South Korea’s IBS Centre for Quantum Nanoscience. “You have to be small to see small.”
