Scattering and Interference in Epitaxial Graphene

Abstract

Our results suggest that effective voluntary suppression of emotional memory only develops with repeated attempts to cognitively control posterior brain areas underlying instantiated memories. In this sense, memory suppression may best be conceived as a dynamic process in which the brain acquires multiple modulatory influences to reduce the likelihood of retrieving unwanted memories. A single sheet of carbon, graphene, exhibits unexpected electronic properties that arise from quantum state symmetries, which restrict the scattering of its charge carriers. Understanding the role of defects in the transport properties of graphene is central to realizing future electronics based on carbon. Scanning tunneling spectroscopy was used to measure quasiparticle interference patterns in epitaxial graphene grown on SiC(0001). Energy-resolved maps of the local density of states reveal modulations on two different length scales, reflecting both intravalley and intervalley scattering. Although such scattering in graphene can be suppressed because of the symmetries of the Dirac quasiparticles, we show that, when its source is atomic-scale lattice defects, wave functions of different symmetries can mix.

Controlling doping in graphene through a SiC substrate: A first-principles study

“…This approximation has been proved to well describe the electronic properties of epitaxial graphene on SiC 9,11 . More importantly, the √ 3 × √ 3R30 o reconstruction is also been observed in experiments during epitaxial growth of graphene on both (C-terminated) SiC(0001) surface 6,12 and (Si-terminated) SiC(0001) surface [13][14][15] . To address the doping effects in graphene-SiC system, a 2 √ 3 × 2 √ 3R30 o SiC substrate cell, which accommodates a 4 × 4 graphene cell, is constructed.…”

“…The deformed buffer layer as well as the defect reconstruction are responsible for the lower E f of vacancy in buffer layer. In experiments, considerable amounts of defects have been observed in the interface layer of epitaxial graphene system 14,24 , especially the existence of reconstructed hexagon-pentagon-heptagon 24 . The experimental observations indicate that the E f of defect in buffer layer is much lower than in FSG, agreeing with our results.…”

Structural Defects in Graphene

“…All defects lead to scattering of the electron waves and change the electron trajectories. 100,101 Studies of the influence of structural defects on the electrical properties of graphene have just begun, 101 and there is still a lack of reproducible experimental results, as compared to the vast amount of the available theoretical data. Therefore, the present survey is unavoidably incomplete, and just a snapshot of the present activities can be given.…”

Structure of graphene and its disorders: a review

“…These disorders are able to alter the bond length of the interatomic bonds and lead to the re-hybridization of and orbitals. Moreover, all defects may cause the scattering of electron waves and change the electron trajectories [237,238]. As a result, the electronic structure in the vicinity of these disorders differs from that in a perfect lattice.…”