Hot Stuff: Beating the heat in computers generally means attaching a heat sink and a fan to a microprocessor. But for the heat to get out of the chip, the interfaces between the chip and its package lid, if there is one, and the lid and the heat sink must be filled with a thin layer of thermal interface material [see inset]. This heat-conducting material draws heat out by also filling the microscopic gaps in the not quite flat surfaces. Ordinarily the gaps contain air, a poor heat conductor. Recently, researchers have been turning to nanoscale materials to fill the even smaller gaps that traditional interface materials cannot get into.