A study of the poly(dA)-poly(dT) DNA electric field-dependence: density of states (DOS) analysis

Abstract

Study of poly(dA)-poly(dT) DNA molecule electronic structure, by analysing its density of states (DOS), had been conducted. This research employed Green’s function method as tool to determine electron DOS of the DNA numerically. Electric field that was applied along z-axis is used as perturbation to modify electron hopping constant between sites in the molecule. In order to include electric field in the calculation, Miller-Abraham formula was used. Medium interaction with backbone molecules was considered as well within the calculation in the form of backbone disorder. By increasing electric field, the band in electron DOS spectrum appeared to become narrower and several states experience the decrement of DOS.

Investigating magnetoresistance properties on a periodic poly(dA)-poly(dT) DNA structure

“…In the model used in this study, left and right metallic electrodes are used to sandwich the DNA structure. The electrode also is written in a tight-binding scheme using onsite energy of 8.45 (equal to Fermi energy) and the electron hopping constant of 0.75 eV [23]. The contacts between each end of the DNA molecule with one electrode are also expressed in the tight-binding Hamiltonian scheme using an electron hopping constant of 0.75 eV [23], which manifests as the self-energy (Σ).…”

“…The variable 𝜀 𝑖 𝜏 is used to measure the onsite energy at the site 𝑖 and strand . Its values used in this study are 8.22, 9.06, and 9.36 eV for Adenine, Thymine, and sugarphosphate consecutively [23]. In this study, the electron is considered to be able to hop from one position to the other, represented by the parameter 𝑡 𝑖,𝑗 𝜏,𝜎 .…”

“…Assuming that DNA structure is placed along the z-axis, where 𝑧 𝑖 is the z coordinate of the site 𝑖. When a particle with charge q jumps from site 𝑗 to site 𝑖 in a medium with dielectric constant Κ and electric field magnitude F at temperature T, its hopping parameter can be expressed as [23] 𝑡 𝑖,𝑗 = { 𝑡 0 𝑒𝑥𝑝 ( 𝑞𝐹 𝛫𝑘 𝐵 𝑇 (𝑧 𝑖 − 𝑧 𝑗 )) ; 𝑖𝑓 (𝑧 𝑖 − 𝑧 𝑗 ) < 0 𝑡 0 ; 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒 .…”

Magnetic Field-Dependent Electric Current on a Periodic Poly(da)-Poly(dt) Dna Molecule Structure

“…In this investigation, the internal electric field is present in the DNA molecule as a result of the voltage difference between the two metallic electrodes. Therefore, the electric field considered is in the direction of the symmetrical axis of the DNA molecule (z-axis) and causes the hopping parameter of a particle with charge q which moves from site j to site i can be stated as follow [23].…”