Cotunneling in single-electron devices: Effects of stray capacitances.

An analytic treatment of the effects of stray capacitances on cotunneling in single-electron devices with equal junction capacitances is presented. By using analytical forms of the Gibbs free energy and by extending the Jensen-Martinis approximation @Phys. Rev. B 46, 13 407 ~1992!#, we have calculated the threshold voltages and currents for cotunneling in one-dimensional arrays, single-electron traps, and single-electron turnstiles. Our results show that the main effect of the stray capacitances on the cotunneling is to reduce the threshold voltages, whereas it has very little effect on the magnitude of the tunneling current. In general, when the stray capacitances increase, the current-voltage curve of the single-electron device is shifted towards the low-voltage side. The relevance of our theoretical results to some experiments are also discussed. @S0163-1829~96!06044-4#