Eur. Phys. J. B (2013) 86: 103
https://doi.org/10.1140/epjb/e2013-30728-9

Regular Article

Electronic localization at mesoscopic length scales: different definitions of localization and contact effects in a heuristic DNA model

¹ Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Rua Sérgio Buarque de Holanda, 777 Cidade Universitária, 13083-859 Campinas, SP Brazil
² Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, 13484-350 Limeira, SP Brazil

^a e-mail: cjpaezg@ifi.unicamp.br

Received: 6 August 2012
Received in final form: 9 January 2013
Published online: 18 March 2013

Abstract

In this work we investigate the electronic transport along model disordered DNA molecules using an effective tight-binding approach, addressing the localization properties. Different tools to investigate the degree of localization are examined as a function of system length, energy dependence and DNA to electrode coupling: localization length, participation number and sensitivity to boundary conditions. Combining the results obtained from these different tools, a thermodynamic limit for the model DNA molecule, within the mesoscopic length scale, can be established. Furthermore, three aspects are investigated: (i) the influence of strongly localized resonances on the localization length is discussed as an important mechanism defining the degree of localization for sizes below the thermodynamic limit; (ii) the dependence on the Hamiltonian parameters on a possible diffusive regime for short systems; and, finally, (iii) possible length dependent origins for the large discrepancies among experimental results for the electronic transport in DNA samples.