nnano.2007.127 ThisIssue.indd

Identifying suitable two-state systems to act as quantum bits or ‘qubits’ is an important first step in any effort to design and build a quantum computer. One approach is to use a voltage to control the direction of electron spins (which can point up or down) in semiconductor quantum dots. However, spin qubits based on molecular magnets could have a number of advantages, including the possibility of using chemical methods to assemble large numbers of identical qubits, if they could be controlled by all-electrical methods. Daniel Loss and colleagues propose that polyoxometalate molecules containing two magnetic vanadium oxide units separated by a molybdenum oxide core may be a viable system. They predict that a voltage applied with a scanning tunnelling microscope could switch and read out the state of the electron spins on the vanadium atoms. [Article p312; News & Views p271]