2019 Isaac Newton Medal and Prize
Professor Sir Michael Pepper for the creation of the field of semiconductor nanoelectronics and discovery of new quantum phenomena.
Michael Pepper is nominated for his creation of the new, important field of semiconductor nanoelectronics and electron manipulation and the discovery of new, unsuspected, phenomena.
Early work investigated Mott-Anderson localization, the first quantum Hall paper and the subsequent dependence of quantization on localization.
Semiconductor nanoelectronics started with the work of Pepper and his group, showing that electrostatic manipulation of electrons by patterned gates converted a two-dimensional electron system into one dimension, first in Silicon then GaAs, followed by the first lateral, zero-dimensional quantum dot showing what was subsequently explained as Coulomb Blockade.
The 1D quantized conductance was found by Pepper's group and another group using his patterned gate technique. A spontaneous spin polarization, the 0.7 structure, was discovered stimulating an enormous literature. Other design innovations to investigate basic physics include remote detection of single electrons, widely used for information read out in quantum computation, gigahertz pumping of single electrons, now being exploited by standards laboratories for high accuracy measurements of electron charge.
Interactions and spin-orbit coupling were used to control spin texture, and further investigations found the spin incoherent state in which the spin is indeterminate. A remarkable new effect which he and his group discovered and published last year, generating great interest, is the discovery of non-magnetic fractionally quantized conductance which has been sought since shortly after the discovery of the Fractional Quantum Hall effect, in 1982. The electron-electron interaction splits a weakly confined line of electrons into two, the start of the long-sought Wigner Lattice, and then a further reorganisation of electron configuration gives the new fractional quantization.
Pepper has developed applications of semiconductor nanostructures by starting the Quantum Communications programme at Toshiba, Cambridge, where he was the founding Managing Director, leading to controlled single and entangled photon devices and applications. He also co-founded TeraView which is commercialising terahertz using semiconductor emitters/detectors. Here his team discovered terahertz detection of cancer and developed industrial applications of the technology.
Pepper is continuing to define the frontier of physics, as he has in the past, finding effects of importance for basic physics and emerging technologies.