Transverse tunneling current through guanine traps in DNA

The current - voltage dependence of the transverse tunneling current through the electron or hole traps in a 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.