Tight-Binding Model for DNA Double Chains: Metal–Insulator Transition Due to the Formation of a Double Strand of DNA

A tight-binding model is formulated for the calculation of the electronic structure of a double strand of deoxyribonucleic acid (DNA). The theory is applied to DNA with a particular structure such as the ladder and decorated ladder structures. It is found that there is a novel type of metal–insulator transitions due to the hopping anisotropy of the system. A metal-semimetal-semiconductor transition is found in the former and an effective semiconductor-metal transition at finite temperature in the latter, as the effect of base paring between two strands of DNA is increased. The latter mechanism may be responsible for explaining the Meade and Kayyem's recent observation.