Inelastic quantum transport in a ladder model: Implications for DNA conduction and comparison to experiments on suspended DNA oligomers

Abstract

We investigate quantum transport characteristics of a ladder model, which effectively mimics the topology of a double-stranded DNA molecule. We consider the interaction of tunneling charges with a selected internal vibrational degree of freedom and discuss its influence on the structure of the current-voltage characteristics. Further, molecule-electrode contact effects are shown to dramatically affect the orders of magnitude of the current. Recent electrical transport measurements on suspended DNA oligomers with a complex base-pair sequence, revealing strikingly high currents, are also presented and used as a reference point for the theoretical modeling. A semi-quantitative description of the measured I-V curves is achieved, suggesting that the coupling to vibrational excitations plays an important role in DNA conduction.

Thermopower of molecular junctions: Tunneling to hopping crossover in DNA

“…In other methods, one explicitly includes the interaction of transport charges with selected DNA vibrational modes using e.g. Green's function approaches 80 , quantum rate equations 81 , or semiclassical approximations 82 .…”

“…Refs. 71,80,[84][85][86] . This Hamiltonian describes the topology of a ds-DNA molecule which is n base-pairs long, with each site representing a particular base; N = 2n is the total number of bases.…”

Electrical Conductance in Biological Molecules

“…Usually, tight-binding Hamiltonians are employed to describe electronic structures of DNA duplexes -both explicitly (in the form of the "fishbone", "ladder" and similar models -see, for example, [51,53,58,60,[64][65][66][67][68][69][70][71][72] and the pertinent review articles [3,[73][74][75][76][77] ) and implicitly (within the framework of Marcus-type theories of charge transfer, for example, [55,[78][79][80][81] and the references therein). These works were successful in qualitatively (and sometimes even quantitatively) describing numerous experimental data (see, for example, [42,56,57,82,83] and the references therein) on transfer of injected single holes (or injected single electrons) through DNA duplexes.…”

Electrical conductance in duplex DNA: Helical effects and low-frequency vibrational coupling

“…The role of thermal fluctuations on the charge transfer efficiency has been discussed in a number of recent papers where the structural fluctuations of the DNA double helix are described by sampling the initial angular velocities and twist angles from a Boltzmann distribution at a given temperature. [18][19][20][21][22][23][24] In this work we will focus on coherent transport due to the coupling between low-frequency vibration modes and charge motion through duplex DNA, and we will explicitly take into account its characteristic helical geometry.…”