Physico-Chemical nanomaterials science

Extended quasi-correlated orbitals and their application to organic single-molecule electronics

Luzanov A.V.1
1 State Scientific Institution “Institute for Single Crystals”, Natl.Acad. of Sci. of Ukraine. 1, Nauky av 60.,UA-61001, Kharkiv, Ukraine.
E-mail: avluzanov@gmail.com

We propose a simple and efffective way to improve the tight-binding (TB) and related approaches to molecular conductance for organic nanoelectronics problems. The conventional TB and  previously given  quasi-correlated TB , i.e., QCTB [1], schemes are very feasible and easy to implement but suffer from neglecting completely physically important long-range Coulomb interaction terms. To overcome this disadvantage the extended quasi-correlated orbital (EQCO) model is presented in our work. It is based on QCTB scheme which includes the usual Hartree-Fock-type Coulomb terms computed with a TB electronic distribution. In practice, EQCO is of a similar  degree of computational complexity as  QCTB, but unlike TB and even QCTB, the new model provides a good performance in the Green function computations for typical nanosized p-conjugated networks. Besides, we suggested several suitable interpretative indexes  (distance correlators, collectivity numbers  (for multichannel or multi-probe devices) and others) which help us to undersrand physical peculiarities of the studied single-molecule junctions. The  elaborared EQCO methof is illustrated by computations on some junctions based on  graphene  quantum dots which were studied from another angle in Refs. []
1.	Luzanov A. V. Effectively Unpaired Electrons for Singlet States: From Diatomics to Graphene Nanoclusters // in Practical Aspects of Comput. Chemistry IV (Springer US, Boston, MA, 2016), PP. 151–206.