Short-range order in linear binary alloys: Delocalization of states versus memory of ordered band structures

Abstract

We discuss the electronic properties of a one-dimensional tight-binding model for binary alloys with correlated disorder. The correlation inhibits the bonds between atoms of one of the atomic species, leading to what is called repulsive binary alloys. As it is well known, the transmission probability of repulsive binary alloys shows resonances due to the delocalization of states in this peculiar disordered one-dimensional system. We show that this delocalization can be related to the memory of the band structures of different ordered chains, since short segments of these ordered chains constitute the repulsive binary alloy. This memory effect is revealed in the localization length as a function of energy. The same argument is used to show that competing correlations in the same linear chain destroy delocalization, as can be inferred from the properties of binary alloys with no correlations at all. We also show that, complementary to delocalized bands, smooth transmission gaps should also exist at specific energy ranges only for correlated disorder cases. ͓S0163-1829͑96͒10133-8͔

Thermal Properties of Ordered and Disordered DNA Chains: Efficient Energy Conversion

“…However, if the system presents bonding between first neighbors type B bases, we speak of a disordered system uncorrelated. [23,[25][26][27] For the ordered case the probability P B ¼ 1.…”

“…In this case the system behaves as the “Repulsive binary alloy“ model. However, if the system presents bonding between first neighbors type B bases, we speak of a disordered system uncorrelated . For the ordered case the probability .…”

“…Thus, to have a complete idea about ZT, we need to explore all these different thermoelectric quantities. We model the DNA molecule using the standard tight-binding (TB) framework within a nearest-neighbor approximation, and calculate the electronic transmission using the transfer matrix formalism, [23][24][25][26][27][28][29][30] while the thermoelectric quantities are evaluated based on the Ladauer prescription. [31][32][33][34][35][36] Depending on the arrangements of two base pairs A and B (see Figure 1), we can have ordered and disordered DNAs, and, we will concentrate on both these two cases to make the present communication a self contained one.…”

Statistical Characterization of the Energy Spectrum in 1D Disordered Multilayer Systems

“…However, in recent years, a number of models [3][4][5] predict that, as a consequence of the introduction of short range correlations, there are sets of extended states in a determined energy region. One of these models is called the repulsive binary alloy (RBA), in which the inhibition of bonding between two elements of one of the two atomic species results in the above mentioned correlations [6]. In a previous work we have presented [7] a model of a disordered quantum well consisting of a short portion of RBA within ordered barriers.…”

“…Tight-binding parameters are the same as in Ref. [6]. In a RBA the bond between one of atomic species is inhibited, introducing short range order: in a chain of A and B sites, only A-A and A-B nearest neighbors bonds are allowed.…”