Charge and Spin Transport in Disordered Graphene-Based Materials

Beschreibung

This thesis presents an in-depth theoretical analysis of charge and spin transport properties in complex forms of disordered graphene. It relies on innovative real space computational methods of the time-dependent spreading of electronic wave packets. First a universal scaling law of the elastic mean free path versus the average grain size is predicted for polycrystalline morphologies, and charge mobilities of up to 300.000 cm2/V.s are determined for 1 micron grain size, while amorphous graphene membranes are shown to behave as Anderson insulators. An unprecedented spin relaxation mechanism, unique to graphene and driven by spin/pseudospin entanglement is then reported in the presence of weak spin-orbit interaction (gold ad-atom impurities) together with the prediction of a crossover from a quantum spin Hall Effect to spin Hall effect (for thallium ad-atoms), depending on the degree of surface ad-atom segregation and the resulting island diameter.
This thesis presents an in-depth theoretical analysis of charge and spin transport properties in complex forms of disordered graphene. It relies on innovative real space computational methods of the time-dependent spreading of electronic wave packets. First a universal scaling law of the elastic mean free path versus the average grain size is predicted for polycrystalline morphologies, and charge mobilities of up to 300.000 cm2/V.s are determined for 1 micron grain size, while amorphous graphene membranes are shown to behave as Anderson insulators. An unprecedented spin relaxation mechanism, unique to graphene and driven by spin/pseudospin entanglement is then reported in the presence of weak spin-orbit interaction (gold ad-atom impurities) together with the prediction of a crossover from a quantum spin Hall Effect to spin Hall effect (for thallium ad-atoms), depending on the degree of surface ad-atom segregation and the resulting island diameter.
Nominated as an outstanding Ph.D. thesis by the Universitat Autònoma de Barcelona, Spain A self-contained treatment with detailed (tutorial style) description of original and innovative quantum transport methodologies Clearly explains predictive modeling for complex forms of two-dimensional materials(graphene and beyond) Useful as a guide to experimentalists and engineers evaluating fundamental properties of graphene-based materials and devices Provides introduction to the essentials of electronic and transport properties in disordered graphene Includes supplementary material: sn.pub/extras

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Dinh Van Tuan

Themen in »Charge and Spin Transport in Disordered Graphene-Based Materials«

Amorphous graphene membranes Anderson localization Charge mobility in disordered graphene Graphene transistors simulation Kubo-greenwood conductivity Order N computational methods Quantum spin Hall effect Quantum transport in graphene Spin Hall effect Spin dynamics and relaxation mechanism Weak and strong localization in graphene

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