First-principles study on electronic transport properties of DNA bases via perpendicular direction of base plane

摘要

Aim. Aim of the paper is to study on the electronic transport characteristics of the four DNA bases via perpendicular direction of the base plane. Methods. By employing the first-principles theory we constructed a theoretical model to perform the calculation by putting the four DNA bases in the middle of the gold[111] nano-electrodes with bases plane parallel to the electrodes surface layer. We first released the optimal distance of the nanoelectrodes and then theoretically calculated the conductance (G) and current (I) of the four DNA bases via perpendicular direction of the base plane. At last, we studied the transmission coefficient (T) of the four bases when they are in zero-bias and low-bias conditions. Results. The optimal electrode distance to study the electronic signature of DNA bases is about 6.8 A and magnitudes of conductance (G), current (I) and transmission coefficient (T) of the four bases are all in the same order of X_T > X_G > X_A > X_C (X=G, I and T) in different low-bias conditions. Low bias voltage on gold nano-electrodes can not change the magnitude order of T around Fermi level about from -0.3eV to 0.5eV and then can not affect the electronic characteristics of the four bases significantly. Conclusion. The four bases display a stable order of values of G, I and T in different low bias conditions. The theoretical study of this paper is meaningful to understand the electronic transport properties of DNA bases and helpful to perform DNA bases recognition and DNA sequencing between two gold nano-electrodes using electronic characteristics method.