  We investigate the charge transport in synthetic DNA polymers built up from
single types of base pairs. In the context of a polaron-like model, for which
an electronic tight-binding system and bond vibrations of the double helix are
coupled, we present estimates for the electron-vibration coupling strengths
utilizing a quantum-chemical procedure. Subsequent studies concerning the
mobility of polaron solutions, representing the state of a localized charge in
unison with its associated helix deformation, show that the system for
poly(dG)-poly(dC) and poly(dA)-poly(dT) DNA polymers, respectively possess
quantitatively distinct transport properties. While the former supports
unidirectionally moving electron breathers attributed to highly efficient
long-range conductivity the breather mobility in the latter case is
comparatively restrained inhibiting charge transport. Our results are in
agreement with recent experimental results demonstrating that poly(dG)-poly(dC)
DNA molecules acts as a semiconducting nanowire and exhibits better conductance
than poly(dA)-poly(dT) ones.
