Rumford Professor of Physics and Gordon McKay Professor of Applied Physics
Massachusetts Institute of Technology
Michael Tinkham's research has focused on superconductivity for many years, as recorded in his textbook on the subject, but in recent years he has been particularly active in studying the unique properties of materials when sample dimensions are reduced to the nanometer range. Such studies are motivated both by their intrinsic scientific interest and by their potential importance in finding new ways to fabricate ultracompact electronic components on a molecular size scale.
For example, nanoscale metallic grains have such small capacitance that the electrostatic energy cost of a single excess electron exceeds thermal energies, and the number of electrons can be controlled one-by-one even when there are a billion electrons on the grain. Also, the discrete "particle in a box" quantum energy levels can be resolved by tunneling experiments at low temperatures.
The transport properties of superconducting nanowires and single-walled carbon nanotubes are also studied. The nanowires appear to show resistance all the way down to absolute zero, thanks to macroscopic quantum tunneling processes of the phase of the superconducting wave function. In the carbon nanotubes, we have observed resonant scattering by both natural and artificial defects, and also Fabry-Perot interference patterns stemming from quantum electron waves traveling in the nanotube in analogy to electromagnetic waves in a waveguide.