Transmission of double-impurity atomic switches

Effect of molecular wires attached to benzene: Local density-of-states study

“…Following a common approach, [10][11][12][13]25 both the benzene molecule and the polymeric chains are described by tightbinding Hamiltonians with site ͑bond͒ energies ␣ (␤). Although this model is certainly too simplified to explain all the characteristics of realistic molecular circuits, it does permit analytical results and, more importantly, has proven to provide qualitative understanding of essential electronic and transport properties of -conjugated polymers.…”

Transmission Properties of Branched Atomic Wires

“…The impurities, at the sites n = 0 and n = d, have modified site energies α a and α b , respectively, with the obvious feature that the system reduces to a one-impurity chain by setting α b = α. Transmission through such a wire for the case of no overlap (S = 0) has been treated by Mišković et al [8], from which the extension to the case S = 0 is straightforward, using the method of reference [7]. To this end, with some changes in notation, the Mišković equation ( 21) for the transmission probability becomes…”

“…is the renormalized site energy. Thus, equation (10) has been eliminated, leaving the system of equations as (8) along with (12), and represented schematically by Figure 2(b). The procedure can be extended to more complicated systems, as will be seen in the next section, by eliminating sites, one-by-one, starting at the end of a branch, which corresponds mathematically to recursive application of (13) to produce the renormalized site energy at the "root" site, which appears as an impurity in the chain.…”

“…As we are considering such attachments at either one or two sites, such systems can thus be reduced to atomic wires with one or two impurities. As previously mentioned, the former has been considered by us [7], while the latter has only been treated in the zero-overlap case [8]. Thus, the methodology, discussed in the next sections, firstly extends the theory of electron transmission through double-impurity wires, so as to incorporate overlap, which is similar to the single-impurity theory, then, secondly, uses the renormalization technique to reduce complicated branched structures to single atomic wires containing one or two impurities.…”

Linking model Hamiltonians to ab initio and semiempirical methods in descriptions of impurities in conjugated polymers

“…Molecular electronics is emerging as a promising field of research and a powerful source of technology 1–6. The manipulation of single molecules opens the possibility of the creation of a wide range of functional devices that mimic the solid‐state ones, and may also have other new and important characteristics and functions.…”