Transverse tunneling current through guanine traps in DNA

The current-voltage dependence of the transverse tunneling current through the electron or hole traps in DNA is investigated. The hopping of the charge between the sites of the trap and the charge-phonon coupling results in a staircase structure of the I-V curve. For typical parameters of the DNA molecule, the energy characteristics of a DNA trap can be extracted from the I-V dependence, viz., for a small gate voltage the phonon frequency, and for a large gate voltage the hopping integral can be found from the positions of the steps in the I-V curve. Formation of the polaronic state also results in the redistribution of the tunneling current between the different sites of the traps.