With multiple grants and research infrastructure provided by the U.S. National Science Foundation, researchers at Stanford University have shown that a newly developed material, niobium phosphide, can conduct electricity better than copper in films that are only a few atoms thick. These films can also be created and deposited at sufficiently low temperatures for compatibility with modern computer chip fabrication \u2014 and may help make future electronics more powerful and energy efficient.<\/p>\n
So far, the best conductor candidates to outperform copper in nanoelectronics have crystalline structures, requiring high temperatures to be formed. These new niobium phosphide films are the first examples of noncrystalline materials that become better conductors as they get thinner.<\/p>\n
\u201cWe are breaking a fundamental bottleneck of traditional materials like copper,\u201d says Asir Intisar Khan, a postdoctoral researcher at Stanford and an author on the research paper published in Science<\/em>. \u201cOur niobium phosphide conductors show that it’s possible to send faster, more efficient signals through ultrathin wires. This could improve the energy efficiency of future chips, and even small gains add up when many chips are used, such as in the massive data centers that store and process information today.\u201d<\/p>\n Niobium phosphide is a topological semimetal; it can conduct electricity, but its outer surfaces are more conductive than its inner material. The thinner a niobium phosphide film is made, the smaller its inner material gets \u2014 but its surfaces stay the same. This allows its more conductive outer surfaces to contribute more to electrical currents and make for better conductive material. \u201cReally high-density electronics need very thin metal connections, and if those metals are not conducting well, they are losing a lot of power and energy,\u201d says Stanford professor Eric Pop, senior author of the study. \u201cBetter materials could help us spend less energy in small wires and more energy actually doing computation.\u201d<\/p>\n Niobium phosphide films are a new frontier for conductors in nanoelectronics. However, the researchers don’t anticipate that they will suddenly replace copper in all computer chips \u2014 copper continues to be a superior conductor in thicker films and wires. Niobium phosphide could nonetheless be used for the very thinnest connections and opens doors to researching other topological semimetals as conductors that could take niobium phosphide’s performance even further.<\/p>\n <\/p>\n
\nBy comparison, traditional conductive metals like copper become worse at conducting electricity when thinner than about 50 nanometers.<\/p>\n