Extrinsic Semiconductor Character of a Double Strand of Dna: Holstein’s Polarons as Donors and Acceptors

We study the electrical conductivity problem of DNA, applying the Holstein’s polaron model to a double strand of DNA. We show that the Holstein’s polarons act as donors and acceptors in DNA and that the existence of such donors and acceptors provides us the extrinsic semiconductor character of DNA. This character of DNA may explain with a unified point of view almost all the known results recently obtained by experiments in the study of conductivity problems of DNA, which seem so controversial so far.