Unfazed by imperfections
While insulating against electrical currents in their interior, the surface of materials called topological insulators permits the flow of electron spins relatively unhindered. The almost lossless flow of spin information makes topological insulators a promising new class of materials for electronic applications: the electron spins could be harnessed to transmit information in the same way that electrical charges are used in conventional electronics. Electron spins are also susceptible to magnetic fields, so electrical control of the magnetic fields of these materials would offer further control over the properties of electronic devices. Magnetic impurities in these materials, however, have thwarted attempts by experimental physicists to fabricate topological insulators, because they destroy the characteristic energy structure of a topological insulator (Fig. 1).
