In March 2018, researchers at the Massachusetts Institute of Technology, Harvard University, and the Lawrence Berkeley National Laboratory published research describing the development of a metallic crystal with unusual electronic properties. The crystal adopted a kagome crystal structure in which iron and tin atoms form a network of corner-sharing triangles akin to the pattern of Japanese kagome weaved baskets. The researchers claim that the metallic kagome crystal conducts electricity with zero energy loss at room temperature and that current flows in a circular path at the edges of the crystal. They fabricated the kagome crystal, measuring about 1 millimeter in length, by annealing iron and tin powders with a shape-forming additive at 750 degrees Celsius (°C), followed by quenching. The researchers, whose work appeared in the scientific journal Nature, ascribed the kagome crystal's unusual electronic properties to quantum effects and magnetic effects arising from the material's crystal structure and its iron constituent.

Implications

The development of high-temperature superconductors—materials that conduct electricity without resistance and, therefore, loss of power—is a holy grail for scientists and technology developers spanning many application fields. A handful of metallic materials are superconductive at ambient pressure when cooled to ultralow temperatures below approximately –135°C. However, cooling materials to such low temperatures is expensive and challenging to perform at large scales, and the commercial use of superconductive materials is limited to a few specialist applications. Therefore, much research is under way to develop materials that are superconductive at ambient temperature and pressure. The kagome material is promising because it conducts electricity without losing energy at room temperature and could serve as a precursor for the development of materials with high-temperature superconductive properties.

Impacts/Disruptions

Room-temperature superconductors could pave the way for next-generation technologies that revolutionize a variety of industries. For example, the technology could offer major energy and cost savings to power-generation, -transmission, and -storage applications. Ambient-temperature superconductors could enable ultrafast and ultra-low-power electronics and the development of novel communications and quantum-computing technologies. Although many drivers exist for the development of room-temperature superconductors, the technology is still hypothetical and certainly many years from commercialization.

Kagome metals are at the proof-of-concept stage, and whether the material proves to be a room-temperature superconductor remains a question. Further research will be necessary to understand the underlying physics of kagome metals and determine whether these materials have sufficient power density for practical applications. Although the researchers fabricated the kagome material using a relatively straightforward technique, mass-producing the material in device-compatible forms may prove challenging.