Novel Materials for Quantum Computing

Wednesday, August 1, 2007 - 12:00pm - 12:30pm
EE/CS 3-180
Nicholas Harrison (Imperial College London)
The controlled transport of spin polarised electrons on a 1 nanometre length scale is a realistic prospect and could be the basis for new multifunctional devices with a component density an order of magnitude higher than current VLSI technology. The fundamental materials chemistry challenge is to produce a nano-structured semiconductor that is ferromagnetic at room temperature. Ideally the electronic and magnetic properties need to be robust but tunable through control of composition and structure.

The results of recent high quality theoretical calculations on a number of pure carbon materials will be presented. A novel mechanism for long range magnetic coupling in extended pi-bonded systems will be discussed and documented with explicit calculations on graphene ribbons and defective graphene sheets. A putative ordered defect phase which gives rise to a semiconducting ground state that is ferromagnetic at room temperature will be presented. It will also be shown that the band gap and magnetic coupling may be controlled by varying the defect density.