Since the discovery of X-rays by Wilhelm Röntgen in 1895, its use has been ubiquitous, from medical and environmental applications to materials sciences. X-ray characterization requires a large number of atoms and reducing the material quantity is a long-standing goal. Argonne National Laboratory researcher Saw Wai Hla and colleagues now show that X-rays can be used to characterize the elemental and chemical state of just one atom.
“Atoms can be routinely imaged with scanning probe microscopes, but without X-rays one cannot tell what they are made of,” said Dr. Hla, who is also the director of the Nanoscale and Quantum Phenomena Institute at Ohio University.
“We can now detect exactly the type of a particular atom, one atom-at-a-time, and can simultaneously measure its chemical state.”
Dr. Hla and co-authors conducted their experiment at the XTIP beamline at the Advanced Photon Source and the Center for Nanoscale Materials at Argonne National Laboratory.
For demonstration, they chose an iron atom and a terbium atom, both inserted in respective molecular hosts.
To detect X-ray signal of one atom, they used a technique known as synchrotron X-ray scanning tunneling microscopy.
“X-ray characterization of materials has been revolutionized after the invention of synchrotron X-rays in the mid-twentieth century,” they said.
“The capabilities of synchrotron light sources have been continuously upgraded to improve resolution and minimum sample quantity required for measurements.”
“So far, an attogram amount of sample can be detected by X-rays. However, it is still in the range of over 10,000 atoms and gaining access to a much smaller sample is becoming extremely arduous.”
“If X-rays could be used to detect just one atom, it would further revolutionize their applications to an unprecedented level, from quantum information technology to environmental and medical research.”
“One way to overcome these challenges is to supplant conventional…
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