Atomic Swiss Knife accurately measures materials for quantum computers

Scientists from the National Institute of Standards and Technology (NIST) have developed a new “three in one” device that can simultaneously perform three types of measurements at the atomic scale. Together, these measurements can open up new knowledge about a wide range of special materials that are critical to the development of next-generation quantum computers, communications, and many other applications. The study is published in the journal Review of Scientific Instruments.

From smartphones to multicookers, devices that perform several functions are often more convenient and potentially cheaper than the universal tools that they replace, and their many functions often work better than individually. The new “three in one” instrument is a kind of Swiss army knife for measurements on the atomic scale. NIST researcher Joseph Strossio and his colleagues, including Johannes Schwenk and Sungmin Kim, present a detailed recipe for creating the device.

We describe our plan to create a device for other people so that they can copy it. They can modify their tools; they no longer need to buy new equipment.

Joseph Strossio, NIST Researcher

By simultaneously measuring from nanometers to millimeters, the instrument can help researchers focus on the atomic origin of some of the unusual properties of materials. They can be invaluable for next-generation computers and communication devices.

Properties that scientists are interested in include the flow of electric current without resistance, as well as quantum surges in electrical resistance, which can serve as new electrical switches. In addition, researchers are interested in new methods for designing quantum bits – they can lead to the creation of solid-state quantum computers.

For quantum materials, which usually consist of one or more atomically thin layers, strong quantum effects between groups of electrons persist over long distances. These effects lead to those properties that can be used for new technologies.

To more accurately study the properties of quantum materials, scientists combined three precision measuring instruments in one device. Two devices — the atomic force microscope (AFM) and the scanning tunneling microscope (STM) —examine the microscopic properties of solids. At the same time, the third instrument registers the macroscopic properties of magnetic transfer — the current flow in the presence of a magnetic field.

To create the device, scientists developed an AFM and a magnetic measuring device, which would be more compact and have fewer moving parts than in previous versions. They then integrated the tools with the existing STM.

Both STM and AFM use a pointed tip to examine the atomic structure of surfaces.

The ensemble is installed inside a cryostat, a device that cools the system to one-hundredth of a degree above absolute zero. At this temperature, the random quantum jitter of atomic particles is minimized, and large-scale quantum effects become more pronounced and easier to measure. The three-in-one device, which is protected from external electrical noise, is also 5–10 times more sensitive than any previous set of similar devices.

Although three completely independent instruments — STM, AFM, and magnetic transport — can perform the same measurements, their movements can disrupt sampling and reduce the accuracy of the analysis. Individual instruments can also make it difficult to copy exact conditions. For example, such as temperature and the angle of rotation between each ultrathin layer of a quantum material at which previous measurements were made.