We consider bias-induced circular current in a molecular ring junction. It is natural to define circular current as a component of ring current that acts as a sole source of magnetic flux induced in the ring. Alternatively, the bias-induced circular current can also be determined from the magnetic response of the ring junction to an external flux in the zero-flux limit. This leads to determination of bias-induced circular current without actually calculating the bond currents. We also explore the possibility of circular current-induced force rupturing the covalent bonds in the ring leading to ultimate breakdown of the ring junction. Our calculations underscore the reliability problem posed by the current magnification effect in the molecular ring structures.

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