Nanoelectronics and quantum transport of dirac particles

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Rostam Zadeh, Saber (2019) Nanoelectronics and quantum transport of dirac particles. [Thesis]

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Abstract

In this thesis, we concentrate on the charge and spin transport in Dirac materials and discuss their implications in future electronic technologies. These materials are known for their peculiar band structures, which, unlike the conventional semiconductors, is effectively described by the massless Dirac equation, and their spectrum possesses Dirac nodes. We particularly consider two members of this class of materials: graphene and Weyl semimetals. We first investigate the manipulation of the electronic properties of graphene via adatom engineering. We demonstrate that adatom deposition induces a strong spin-orbit interaction in graphene and, furthermore, couples the spin and valley degrees of freedom, which, in turn, allows for the realization of the valley assisted spin transport and vice versa using a spin-valley device. We also show that the coupled degrees of freedom of graphene due to the presence of disorder causes the intrinsic accumulation of pseudospin charge and pseudospin polarization, which, as we demonstrate, can be used to construct a pseudospin switch device built from a graphene nanoribbon. We next study the Weyl semimetals, as the three-dimensional version of graphene, which has attracted strong interest from the fundamental viewpoint, where they constitute a low energy framework to study the quantum anomalies of the field theory. The electronic structure of these materials is also interesting owing to the fact that the tilting of the band crossing point causes giant electronic conduction and hence a more favorable feature for the electronics industry. We then study the quantum kinetic theory of anomalous transport in these systems to analyze the origin of the chiral anomaly and chiral magnetic effect in Weyl semimetals. Finally, we study the electronic response of tilted Weyl semimetals by associating a relativistic feature to the tiltedWeyl cones and then compare our results with the standard linear response approach. Our calculations show that both the covariant transport equation and Kubo formula methods offer correct and equivalent results which strongly agree with the experimental findings
Item Type: Thesis
Uncontrolled Keywords: Mesoscopic and nanoscale systems. -- Topological phase. -- Spintronics. -- Diffusion. -- Quantum Boltzmann equation. --Relativity. -- Kubo formula. -- Keldysh formalism. -- Meso ve nanoölçekli sistemler. -- Topolojik yalıtkan ve üstüniletkenler. -- Rastlantısal matrisler. -- Spintronik. -- Kuantum termodinamiği.
Subjects: Q Science > QC Physics
Divisions: Faculty of Engineering and Natural Sciences > Basic Sciences > Physics
Faculty of Engineering and Natural Sciences
Depositing User: IC-Cataloging
Date Deposited: 21 Oct 2019 14:03
Last Modified: 26 Apr 2022 10:32
URI: https://research.sabanciuniv.edu/id/eprint/39358

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