October 2021

Researchers from Japan's Tokyo Institute of Technology, National Institute for Materials Science and National Institute of Advanced Industrial Science and Technology have found that lead-based vacancy centers in diamonds, that form after high-pressure and high-temperature treatment, are ideal for quantum networks, spintronics and quantum sensors.

The color in a diamond comes from a defect, or “vacancy,” where there is a missing carbon atom in the crystal lattice. Vacancies have long been of interest to electronics researchers because they can be used as ‘quantum nodes’ or points that make up a quantum network for the transfer of data. One of the ways of introducing a defect into a diamond is by implanting it with other elements, like nitrogen, silicon, or tin. In their recent study, the scientists from Japan demonstrated that lead-vacancy centers in diamond have the right properties to function as quantum nodes. “The use of a heavy group IV atom like lead is a simple strategy to realize superior spin properties at increased temperatures, but previous studies have not been consistent in determining the optical properties of lead-vacancy centers accurately,” says Associate Professor Takayuki Iwasaki of Tokyo Institute of Technology (Tokyo Tech), who led the study.

The attractive properties of Sr₂RuO₄, like its ability to carry lossless electrical currents and magnetic information simultaneously, make it a material with great potential for the development of future technologies like superconducting spintronics and quantum electronics. An international research team, led by scientists at the University of Konstanz, was recently able to answer one of the most interesting open questions on Sr₂RuO₄: why does the superconducting state of this material exhibit some features that are typically found in materials known as ferromagnets, which are considered being antagonists to superconductors?

Spin polarized muon particles (red spheres with arrows) probing a new form of magnetism in the perovskite superconductor Sr2RuO4. Credit: Konstanz University

The team has found that the material hosts a new form of magnetism, which can coexist with superconductivity and exists independently of superconductivity as well.