Nanoscale silicon wires resist quantum predictions

Nature : New research indicates that not everything on a quantum level exhibits quantum behavior. Wires just a few nanometers wide have now been shown to conduct electricity in the same way as the larger components of existing devices. Michelle Simmons, a physicist and director of the Centre for Quantum Computation and Communication Technology at the University of New South Wales in Sydney, Australia, and her colleagues made atomic-scale wires of phosphorous-doped silicon in which the phosphorous provided the extra electrons needed to generate a current, writes Edwin Cartlidge for Nature. Although the width of the wires varied from 1.5 to 11 nm, the resistivity did not differ substantially, thus obeying Ohm’s law of classical electronics. David Ferry, an electrical engineer at Arizona State University in Tempe, noted the importance of the finding to such devices as transistors, which every two years have been shrinking in size yet yielding ever-better performance—a trend known as Moore’s law. If quantum coherence came into play, he said, the transistors wouldn’t turn on and off as expected. Therefore, the new research could have significant implications for the microchip industry. What the implications will be for quantum computing, however, remains to be seen.