Researchers are taking rough, defective diamonds and using high temperatures to perfect them for quantum sensing
Quantum mechanics, the physics that governs nature at the atomic and subatomic scale, contains a host of new physical phenomena to explore quantum states at the nanoscale. Though tricky, there are ways to exploit these inherently fragile and sensitive systems for quantum sensing.
In this study, 3-D images of the strain fields in individual nanodiamond crystals were obtained with Bragg coherent diffraction imaging. With this method, the crystal is illuminated with a coherent X-ray beam which scatters to form a coherent diffraction pattern. A series of these diffraction patterns measured from the crystal are used to reconstruct the 3-D shape and, more importantly, the strain state of the crystal. One such 3-D image of a nanodiamond is shown here, with the surface coloration indicative of local strain.
Credit: Stephan Hruszkewycz
One nascent technology in particular makes use of point defects, or single-atom misplacements, in nanoscale materials, such as diamond nanoparticles, to measure electromagnetic fields, temperature, pressure, frequency and other variables with unprecedented precision and accuracy.
Quantum sensing could revolutionize medical diagnostics, enable new drug development, improve the design of electronic devices and more.
For use in quantum sensing, the bulk nanodiamond crystal surrounding the point defect must be highly perfect. Any deviation from perfection, such as additional missing atoms, strain in the crystalline lattice of the diamond, or the presence of other impurities, will adversely affect the quantum behavior of the material. Highly perfect nanodiamonds are also quite expensive and difficult to make.
A cheaper alternative, say researchers at Argonne National Laboratory and the University of Chicago, is to take defect-ridden, low-quality, commercially manufactured diamonds, and then "heal" them.
In a paper published this week in APL Materials, from AIP Publishing, the researchers describe a method to heal diamond nanocrystals under high-temperature conditions, while visualizing the crystals in three dimensions using an X-ray imaging technique.
"Quantum sensing is based on the unique properties of certain optically active point defects in semiconductor nanostructures," said F. Joseph Heremans, an Argonne National Laboratory staff scientist and co-author on the paper.
These defects, such as the nitrogen-vacancy (NV) centers in diamond, are created when a nitrogen atom replaces a carbon atom adjacent to a vacancy in the diamond lattice structure. They are extremely sensitive to their environment, making them useful probes of local temperatures, as well as electric and magnetic fields, with a spatial resolution more than 100 times smaller than the thickness of a human hair.
Because diamonds are biologically inert, quantum sensors based on diamond nanoparticles, which can operate at room temperature and detect several factors simultaneously, could even be placed within living cells, where they could, according to Heremans, "image systems from the inside out."
Heremans and his colleagues, including Argonne's Wonsuk Cha and Paul Fuoss, as well as David Awschalom of the University of Chicago, set out to map the distribution of the crystal strain in nanodiamonds and to track the healing of these imperfections by subjecting them to high temperatures, up to 800 degrees Celsius in an inert helium environment.
"Our idea of the 'healing' process is that gaps in the lattice are filled as the atoms move around when the crystal is heated to high temperatures, thereby improving the homogeneity of the crystal lattice," said Stephan Hruszkewycz, also a staff scientist at Argonne and lead author on the paper.
This nanodiamond healing was monitored with a 3-D microscopy method called Bragg coherent diffraction imaging, performed by subjecting the crystals to a coherent X-ray beam at the Advanced Photon Source at Argonne. The X-ray beam that scatters off the nanodiamonds was detected and used to reconstruct the 3-D shape of the nanocrystal, "and, more importantly, the strain state of the crystal," Hruszkewycz said.
The researchers found that nanodiamonds "shrink" during the high-temperature annealing process, and surmise that this occurs because of a phenomenon called graphitization. This phenomenon occurs when the surface of the material is converted from the normal diamond lattice arrangement into graphite, a single layer of chicken-wire-like arranged carbon atoms.
The study marks the first time that Bragg coherent diffraction imaging has been shown to be useful at such high temperatures, a capability that, Hruszkewycz said, "enables the exploration of structural changes in important nanocrystalline materials at high temperatures that are difficult to access with other microscopy techniques."
Hruszkewycz added that the research represents "a significant step towards developing scalable methods of processing inexpensive, commercial nanodiamonds for quantum sensing and information processing."
The article, "In-situ study of annealing-induced strain relaxation in diamond nanoparticles using Bragg coherent diffraction imaging," is authored by Stephan O. Hruszkewycz, Wonsuk Cha, Paolo Andrich, Christopher P. Anderson, Andrew Ulvestad, Ross Harder, Paul Fuoss, David D. Awschalom and F. Joseph P. Heremans. The article appeared in the journal APL Materials Feb. 14, 2017 (DOI: 10.1063/1.49748651) and can be accessed at http://aip.
ABOUT THE JOURNAL
APL Materials is a new open access journal featuring original research on significant topical issues within the field of functional materials science. See http://aplmaterials.
AIP Media Line | EurekAlert!
APEX takes a glimpse into the heart of darkness
25.05.2018 | Max-Planck-Institut für Radioastronomie
First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences