Quantum transport in graphene - influence of disorder, electron-phonon interaction, electronic structure and functionalisation

点击翻译按钮获取中文摘要

The project studies the influence of interfaces, disorder and electronic correlations on optical, spectral and transport properties of graphene based structures. Key aspects of our theoretical investigations will be (i) the Dirac electron wave packet time-evolution/dynamics in disordered graphene nanoribbons, (ii) particle scattering off or confinement in gate-defined graphene quantum dots that enable (Veselago) lensing or switching of Klein tunnelling, (iii) current resonances in gated graphene subjected to external time-dependent electromagnetic fields, (iv) phonon-affected non-equilibrium transport through contacted graphene devices, and (v) possible exciton formation and condensation in graphene bilayers. To capture the complex interplay of electronic structure, sample geometry, disorder, electron-electron/phonon and spin-orbit interactions, we use analytical approaches from scattering theory and the Keldysh Green function formalism and combine them with well-conditioned numerical techniques, based on Chebyshev expansion and commutator-free exponential time-propagation. In order to calculate quantities such as the distribution of the local density of states, particle transmission and conductance, the single-particle spectral function or the optical response that characterise the electronic properties and charge transport of real-sized graphene devices, the algorithms are implemented, optimised and run on present-day high-performance supercomputers. Thereby the ultimate objective is to model and understand transport and electronic structure experiments performed by several groups within the DFG priority programme and to demonstrate the functionality of possible building blocks for a graphene based electronics, plasmonics and photonics.