DNA Double Helices for Single Molecule Electronics

Abstract

The combination of self-assembly and electronic properties as well as its true nanoscale dimensions make DNA a promising candidate for a building block of single molecule electronics. We argue that the intrinsic double helix conformation of the DNA strands provides a possibility to drive the electric current through the DNA by the perpendicular electric (gating) field. The transistor effect in the poly(G)-poly(C) synthetic DNA is demonstrated within a simple model approach. We put forward experimental setups to observe the predicted effect and discuss possible device applications of DNA. In particular, we propose a design of the single molecule analog of the Esaki diode. DOI: 10.1103/PhysRevLett.98.096801 PACS numbers: 85.35.ÿp, 85.30.Mn, 85.30.Tv, 87.14.Gg The controversial question of charge transport in DNA molecules has been attracting a great deal of attention recently (see for an overview). The interest in DNA transport properties is at least twofold: on the one hand, the charge migration is believed to be important for the radiation damage repair [4] and, on the other, DNA double helices are expected to be particularly useful for molecular electronics [3,[5][6][7]. While random base sequences are relevant for biological samples, artificially created periodic DNA molecules [8], such as the poly(A)-poly(T) or poly(G)-poly(C), are probably the best candidates for novel device applications. The electrical transport through dry and wet DNA has been extensively studied both theoretically and experimentally and a variety of results has emerged: DNA has been reported to demonstrate proximity-induced superconducting [9], metallic [10 -13], semiconducting [14 -18], and insulating [19,20] behavior. Contact related effects, the impact of the environment, and the DNA base pair sequence lead to such diversity of results. According to both theory and experiment, the dry poly(G)-poly(C) synthetic DNA is a semiconductor: theoretical ab initio calculations predict a wide-band-gap semiconductor behavior (see, e.g., Ref.[21]) while experimental measurements reveal about 2 V voltage gap at low temperature [14].Many effects useful for molecular device applications have been reported: rectification, the Kondo effect, the Coulomb blockade, etc. (see Ref.[7] for a recent overview). In this contribution, it is demonstrated for the first time that the intrinsic helix conformation of the DNA strands determines the transport properties of gated DNA molecules. In particular, we show that the electric current through the double helix DNA (in the base stacking direction) can be driven by the perpendicular gating field. We put forward new experimental setups to reveal the predicted effect and discuss possible applications of the DNA. In particular, we propose a design of the single molecule analog of the Esaki diode.Two approaches are widely used to describe the DNA: ab initio calculations [21][22][23][24][25][26][27][28] and model-based Hamiltonians [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. The former can pr...

Interband optical transitions in DNA-like systems

“…We consider the ladder model 17 of the DNA based on a tight-binding Hamiltonian with few adjustable parameters. Similar models have been previously introduced by several authors [18][19][20][21][22][23][24][25][26][27] to explain the main semiconducting features observed in current-voltage characteristics in dry synthetic poly͑G͒-poly͑C͒ DNA. 1 Intramolecule transitions are beyond the scope of this work, and consequently only a single molecular orbital is assigned to each base.…”

“…However, the spatial arrangement of bases has recently been demonstrated to be crucial for transport properties in the presence of the perpendicular electric field. 27 It can also be relevant when dealing with optical dipole moments of the electronic transitions. To improve the analysis, we consider the double helix structure of DNA molecules: the coordinates of the bases along both strands can be set as…”

“…1 Much earlier, it was predicted by theoretical calculations. 16 Effective Hamiltonian models, based on the tight-binding approximation, [17][18][19][20][21][22][23][24][25][26][27] provide a reasonable description of the semiconductor gap observed in experiments. In this contribution we point out that the underlying electronic band structure with full valence band and empty conduction band suggests that interband optical transitions can occur in DNA.…”

Analysis of the interband optical transitions: Characterization of synthetic DNA band structure

“…However, the spatial arrangement of bases has recently been demonstrated to be crucial for transport properties in the presence of the perpendicular electric field. 34 In addition, it can also be relevant when dealing with optical dipole moments of the electronic transitions. To improve the analysis, we follow Ref.…”

“…21 However, because of the difficulties in manipulating single DNA molecules, it was not definitely established by experiments until much later. 14 Since this crucial experimental goal, several theoretical models [22][23][24][25][26][27][28][29][30][31][32][33][34] have provided a reasonable description of the semiconducting gap observed in the experiments. Although most of these models are based on the effective Hamiltonian models within the tight-binding approximation, there is no complete agreement about the model parameters yet.…”