The configuration of graphene nano-ribbon (GNR) assembly on carbon nanotube (CNT) and sphere is studied through theoretical modeling and molecular simulation. The GNR can spontaneously wind onto the CNT due to van der Waals (vdW) interaction and form two basic configurations: helix and scroll. The final configuration arises from the competition among three energy terms: the bending energy of th...

Recent quantum Hall experiments conducted on disordered graphene p-n junction provide evidence that the junction resistance could be described by a simple Ohmic sum of the n and p mediums’ resistances. However in the ballistic limit, theory predicts the existence of chirality-dependent quantum Hall plateaus in a p-n junction. We show that two distinctively separate processes are required for th...

Materials of the general form MX2 (transition metal dichalcogenides) have generated a lot of interest recently. They can form nanoribbons like graphene and such nanoribbons have versatile electronic structures and can be metallic or semiconducting by changing the edges of the ribbon. The electronic properties of such materials are not fully understood till now. In this paper we investigate one ...

Title of dissertation: BROADBAND PHOTODETECTION IN GRAPHENE Xinghan Cai, Doctor of Philosophy, 2015 Dissertation directed by: Professor, Michael S. Fuhrer, Department of Physics Graphene, a single-atom-thick plane of carbon, has unique optoelectronic properties that result in a variety of potential photonic applications, such as optical modulators, plasmonic devices and THz emitters. In this th...

Quantum interference causes a wavefunction to have sensitive spatial dependence, and this has a significant effect on quantum transport. For example, in a quantum-dot system, the conductance can depend on the lead positions. We investigate, for graphene quantum dots, the conductance variations with the lead positions. Since for graphene the types of boundaries, e.g., zigzag and armchair, can f...

Phonons – quanta of crystal lattice vibrations – reveal themselves in all electrical, thermal and optical phenomena in materials. Nanostructures open exciting opportunities for tuning the phonon energy spectrum and related properties of materials for specific applications. A recent advent of graphene and quasi two-dimensional materials increased the possibilities for controlled modification of ...

The indirect exchange interaction is one of the key factors in determining the overall alignment of magnetic impurities embedded in metallic host materials. In this work we examine the range of this interaction in magnetically doped graphene systems in the presence of armchair edges using a combination of analytical and numerical Green function approaches. We consider both a semi-infinite sheet...