STM control of noninteger residual charge Q/sub 0/ on the central electrode of a double-tunnel junction

In a voltage-biased mesoscopic double-tunnel junction, the Coulomb threshold V/sub C/ is an e-periodic function of Q/sub 0/, the charge on the inner electrode. In the STM work described here, a large Au tip images 100-AA Ag particles deposited on a cleaved BSCCO crystal substrate. Stable double junctions between the tip, the imaged particle, and the substrate are identified by Coulomb staircase I(V)'s. The control of Q/sub 0/ is demonstrated by the variation of tip-particle spacing. The parameterization of such results permits a discussion of Q/sub 0/ variation mechanisms.<
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