Quantized conductance atomic switch

Nanoelectronics switched on A new atomic-scale electromechanical switch has properties that may make it suitable as an element in future nanoelectronic devices. The switch is made by simply crossing a silver sulphide wire and a platinum wire with a 1-nm spacing. When a sufficiently strong voltage pulse is applied, silver atoms from the silver sulphide are electrically introduced into the gap, forming an atomic bridge between the wires; the resulting structure exhibits quantized conduction. The formation process is reversible and the atomic bridge can be annihilated with a second voltage pulse. The ‘crossbar’ structure is convenient for integrating the switch into devices, opening the way for the fabrication of logic circuits using these switches as sole components. A large variety of nanometre-scale devices have been investigated in recent years 1 , 2 , 3 , 4 , 5 , 6 , 7 that could overcome the physical and economic limitations of current semiconductor devices 8 . To be of technological interest, the energy consumption and fabrication cost of these ‘nanodevices’ need to be low. Here we report a new type of nanodevice, a quantized conductance atomic switch (QCAS), which satisfies these requirements. The QCAS works by controlling the formation and annihilation of an atomic bridge at the crossing point between two electrodes. The wires are spaced approximately 1 nm apart, and one of the two is a solid electrolyte wire from which the atomic bridges are formed. We demonstrate that such a QCAS can switch between ‘on’ and ‘off’ states at room temperature and in air at a frequency of 1 MHz and at a small operating voltage (600 mV). Basic logic circuits are also easily fabricated by crossing solid electrolyte wires with metal electrodes.