A calculable quantum capacitance

Kumar, N. (1995) A calculable quantum capacitance Current Science, 68 (9). pp. 945-946. ISSN 0011-3891

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Official URL: http://www.ias.ac.in/j_archive/currsci/68/9/945-94...


The idea of a quantum capacitance is introduced explicitly via the generally valid operational definition based on the quadratic charging energy. The direct quantum capacitance CQ per unit area for a strictly two dimensional metallic bilayer is shown to be l/πaB, where aB = the Bohr radius. This calculable quantum capacitance acts in series with the usual classical capacitance Ccl = ε/4πd, and is independent of the bilayer spacing d, i.e. it has a universal value. Thus, in most cases CQ»Ccl and is, therefore, ineffective. However, for the ultrathin bi/multilayers now grown routinely epitaxially, as also for the bi/multilayers inherent to the layered high-Tc, superconductors, we can have CQ ≤Ccl making CQ dominant. Some possible observable effects are pointed out.

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Deposited On:29 Feb 2012 13:42
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