What is it about?

In our article we studied intrinsic hopping disorder controlled specifically by dimerization force. We note that dimerization force directly implies tunneling dynamics. I. e., the intrinsic disorder parameters are controlled in our results by the numerical relationship between hopping and dimerization force.

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Why is it important?

This work presents an analytical study of electronic transport in dimerized trans-polyacetylene (Trans PA) oligomers containing even (n = 4, 6, 8, 10 sites) and odd (n = 3, 5, 7, 9 sites) chains where the site C 1 is sandwiched by two metallic electrodes (Left and Right). These devices exhibit T-shaped geometry and are investigated by Su-Schrieffer-Heeger (SSH) model via Heisenberg equation of motion combined with the Keldysh formalism. We introduced disorder into the system through the dimerization force (δ) demonstrating that the dimerization in the chain can effectively lead to a linear (low δ) or zigzag (high δ) behavior, besides also suffering increase or decrease in conductance peak [dI/dV]max. The odd chains exhibit trivial topological behavior to which the conductance peaks are suppressed as dimerization disorder is considered-creates barriers for tunneling. On the other hand, we have an opposite behavior for conductance peaks in the even chains. For example, the chain with weak dimerization (low δ) has a perfect transmission for even chains. In addition, we note for odd chains the formation of a plateau in the I–V curve for bias voltages and for even chains that show a linear current. This procedure shows an analytical study through the tunneling of the parameters on the device, such parameters as the tunneling amplitude (Г L/R ) can be accessible experimentally.

Perspectives

Motived by investigation of T-shaped devices, we propose to study the electronic transport properties in finite-sized PA nanowires for chains even-odd type. Experimentally, the study of finite-length chains is relevant. Once, throughout the device, the semiconductor nanowire is considered segmented by disorder in a smaller number of coherent chains. The present model investigated through the control of intrinsic parameters allows the system to behave like a molecular structure like carbyne and even the kitaev’s chain model [5] for topological formation of protected states as observed in photonic quantum walks.

Prof. Dr. Carlos Alberto Brito da Silva Jr.
Universidade Federal do Para

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This page is a summary of: Anomalous Conductance in Trans-Polyacetylene Chains with Even–Odd Parity, Journal of Computational and Theoretical Nanoscience, June 2021, American Scientific Publishers,
DOI: 10.1166/jctn.2021.9722.
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