An individual "dopant" atom has been spied interfering with the flow of electrons through a silicon transistor for the first time. Researchers say the feat could help scientists squeeze more power out of conventional computers and ultimately develop silicon-based quantum computers. Dopants are chemical impurities that affect the flow of electrons through a conducting or semiconducting material. They are deliberately added to pure silicon, for example, to create different types of electronic component. To analyse a lone dopant atom in action, Sven Rogge and colleagues at Delft University of Technology in the Netherlands cryogenically cooled 35-nanometre-wide silicon wires, taken from...