New technique for observing changes at the atomic level could unlock the potential of quantum materials

A research team led by the Department of Energy’s Oak Ridge National Laboratory has developed a unique method for observing changes in materials at the atomic level. This technique opens new avenues for understanding and developing advanced materials for quantum computing and electronics. The article is published in the journal Scientific advances.

The new technique, called Rapid Object Detection and Action System, or RODAS, combines imaging, spectroscopy and microscopy methods to capture the properties of ephemeral atomic structures as they form, providing unprecedented insights on how the properties of materials evolve at the smallest scales.

Traditional approaches combining scanning transmission electron microscopy, or STEM, with electron energy loss spectroscopy, or EELS, have been limited because the electron beam can modify or degrade the materials being analyzed. This dynamic often leads scientists to measure altered states rather than desired properties of materials. RODAS overcomes this limitation and also integrates the system with dynamic computer vision-based imaging, which uses real-time machine learning.

When analyzing the specimen, RODAS focuses only on areas of interest. This approach allows for rapid analysis (in seconds or milliseconds), compared to sometimes several minutes that may be necessary with other STEM-EELS methods. It is important to note that RODAS extracts crucial information without destroying the sample.

All materials have defects, and these defects can directly influence virtually all properties of a material, whether electronic, mechanical, or quantum, for example. Defects can organize in various ways at the atomic level, both intrinsically and in response to external stimuli, such as electron beam irradiation.

Unfortunately, the local properties of these different fault configurations are not well understood. Although STEM methods can measure such configurations experimentally, studying specific configurations without modifying them is extremely difficult.

“Understanding defect configurations is crucial for developing next-generation materials,” said study lead author Kevin Roccapriore of ORNL’s Center for Nanophase Materials Science. “If we had this knowledge, we could intentionally create a specific configuration to produce a specific property. Such work is entirely separate from the activity of observation and analysis, but represents a potentially impactful direction for the future. “

Unlocking the potential of quantum materials

The research team demonstrated their technique on single-layer molybdenum disulfide, a promising semiconductor material for quantum computing and optics applications. Molybdenum disulfide is particularly interesting because it can emit single photons from defects called single sulfur vacancies.

In this material, a single sulfur vacancy refers to the absence of a sulfur atom in its honeycomb structure, which corresponds to the arrangement of the atoms. These vacancies can aggregate, creating unique electronic properties that make molybdenum disulfide valuable for advanced technological applications.

By studying molybdenum disulfide and similar single-layer materials, scientists hope to answer vital questions about optical or electronic properties at the atomic scale.

New frontier in materials science

The RODAS technique represents a significant advance in the characterization of materials. It allows researchers to dynamically explore structure-property relationships during analysis, target specific atoms or defects for measurement as they form, efficiently collect data on various types of defects, adapt to identify new atomic classes or defects in real time and minimize damage to samples while retaining detailed details. analysis.

By applying this technology to a single layer of vanadium-doped molybdenum disulfide, the research team gained a new understanding of the formation and evolution of defects under exposure to an electron beam. This approach allows materials to be explored and characterized in dynamic states, providing deeper insight into how materials behave under various stimuli.

“Materials science techniques such as advanced electron microscopy continue to expand our understanding of the physical world, and systems such as RODAS could play a crucial role in accelerating discovery and innovation,” he said. Roccapriore said.

“The ability to observe and analyze materials at the atomic scale in real time shows the potential to push the boundaries of computing, electronics and beyond, and ultimately enable the development of transformative technologies.”