Researchers in Germany and Korea have fabricated a quantum sensor that can detect the electric and magnetic fields created by individual atoms – something that scientists have long dreamed of doing. The device consists of an organic semiconducting molecule attached to the metallic tip of a scanning tunnelling microscope, and its developers say that it could have applications in biology as well as physics. Some possibilities include sensing the presence of spin-labelled biomolecules and detecting the magnetic states of complex molecules on a surface.
Today’s most sensitive magnetic field detectors exploit quantum effects to map the presence of extremely weak fields. Among the most promising of these new-generation quantum sensors are nitrogen vacancy (NV) centres in diamond. These structures can be fabricated inside a nanopillar on the tip of an atomic force microscope (AFM) tip, and their spatial resolution is an impressively small 10–100 nm. However, this is still a factor of 10 to 100 larger than the diameter of an atom.
The new sensor developed by Andreas Heinrich and colleagues at the Forschungszentrum Jülich and Korea’s IBS Center for Quantum Nanoscience (QNS) can also be placed on a microscope tip – in this case, a scanning tunnelling microscope (STM). The difference is the spatial resolution of this atomic-scale device is just 0.1 nm, making it 100 to 1000 times more sensitive than devices based on NV centres.
To read more, click here.