Scientists from the FRC of Problems of Chemical Physics and Medical Chemistry of the Russian Academy of Sciences, the Institute of Solid State Physics of the Russian Academy of Sciences, and Kyoto University have synthesized a series of coordination compounds that could form the basis for quantum computer processors. The work was supported by a grant from the Russian Science Foundation.
In the obtained complexes, the magnetic moments of atoms (spins) can simultaneously exist in several states – this phenomenon is called quantum coherence. This “coherent uncertainty” persists long enough to transmit information in quantum devices.
The researchers used phthalocyanines as a basis – synthetic organic molecules in the form of a flat ring, similar in structure to natural pigments (chlorophyll and hemoglobin). They are capable of holding metal atoms inside them, which allows for tuning the electronic and magnetic properties of the complexes.
Scientists synthesized three phthalocyanine complexes with metals – vanadium, copper, and tin. Tin was used as a reference: it has no unpaired electrons, so it does not create a magnetic field. In complexes with vanadium and copper, on the contrary, there is one unpaired electron each – their spins behave like quantum objects and demonstrate the coherence effect.
Both materials maintained “uncertainty” for up to 4 microseconds – hundreds of times longer than a standard control pulse. Such a ratio allows these new compounds to be considered promising candidates for creating qubits – the basic elements of quantum processors.
As project leader Maxim Faraonov noted, the research could be a catalyst for creating ultra-miniature devices: ultra-dense information carriers, quantum memory elements, sensors, and magnetic tags. The implementation of such devices will increase the performance, security, and energy efficiency of technology. Scientists plan to modify the complexes to increase the lifetime of quantum coherence – it has already been shown with vanadium that it depends on the method of sample preparation.