## Modelling Electronic Quantum Transport in Nanostructures

**Prof. Antoine Khater**

Department of Physics, Université du Maine, Le Man, France

**24.11.2017, 12:15**, room P/1/14

The decreasing size of nanoelectronic devices takes the electronics technology to the quantum coherent limit. In this seminar the theoretical and numerical computations to model quantum electronic transport across nanostructures are presented; in particular, the transport across nanojunctions in nano circuits is investigated. This is done by generalizing the phase field matching theory (PFMT) to multi-scattering processes, and integrating the Tight Binding into a generalized PFMT-TB approach.

The advantages of the PFMT-TB, as a general, transparent and computation efficient formalism which we have recently developed, are demonstrated for diverse nanostructures, when compared to other computational techniques such as non-equilibrium Green’s functions, and first principle methods, as the DFT for example. This is the case as much as for the computations of localized states at nanostructures embedded in a circuit, as for the computations of Landauer-Buttiker scattering cross sections in quantum transport problems.

The PFMT-TB method can be applied to a large variety of molecular nanojunctions, and is applied here to the nanowire junctions. Our calculations of the band structures for cobalt, copper, carbon, silicon, and diatomic silicon carbide, using the PFMT-TB method, are matched with available DFT results to optimize required TB parameters. The silicon and carbon atoms are treated fully by characterizing each with their corresponding multivalent orbitals. Individual channel contributions to the electronic quantum transport are computed for each eigenmode incident from the nano circuit leads. The results show a number of remarkable features, which include the influence of the ordered periodic configurations of silicon-carbon pairs in nanowire-junctions, and the suppression of the quantum transport due to minimum disorder as much as to artificially organized symmetry.