ROOM-TEMPERATURE SPIN MEMORY IN 2-DIMENSIONAL ELECTRON GASES

Time-resolved Kerr reflectivity of two-dimensional electron gases in I l-VI semiconductors provides a direct measure of electron spin precess ion and relaxation over a temperature range from 4 to 300 kelvin. The introduction of n-type dopants increases the electronic spin lifetimes several orders of magnitude relative to insulating counterparts, a tr end that is also observed in doped bulk semiconductors. Because the el ectronic spin polarization in these systems survives for nanoseconds, far longer than the electron-hole recombination lifetime, this techniq ue reveals thousands of spin precession cycles of 15 gigahertz per tes la within an electron gas. Remarkably, these spin beats are only weakl y temperature dependent and persist to room temperature.