9 research outputs found
A two-dimensional Dirac fermion microscope
The electron microscope has been a powerful, highly versatile workhorse in
the fields of material and surface science, micro and nanotechnology, biology
and geology, for nearly 80 years. The advent of two-dimensional materials opens
new possibilities for realising an analogy to electron microscopy in the solid
state. Here we provide a perspective view on how a two-dimensional (2D) Dirac
fermion-based microscope can be realistically implemented and operated, using
graphene as a vacuum chamber for ballistic electrons. We use semiclassical
simulations to propose concrete architectures and design rules of 2D electron
guns, deflectors, tunable lenses and various detectors. The simulations show
how simple objects can be imaged with well-controlled and collimated in-plane
beams consisting of relativistic charge carriers. Finally, we discuss the
potential of such microscopes for investigating edges, terminations and
defects, as well as interfaces, including external nanoscale structures such as
adsorbed molecules, nanoparticles or quantum dots.Comment: 34 pages; 14 pages; 6 figures; Supplementary informatio
Towards developing efficient metalloporphyrin-based hybrid photocatalysts for CO<sub>2</sub> reduction; an ab initio study
Quantum Interference Engineering of Nanoporous Graphene for Carbon Nanocircuitry
Bottom-up prepared carbon nanostructures appear as promising platforms for
future carbon-based nanoelectronics, due to their atomically precise and
versatile structure. An important breakthrough is the recent preparation of
nanoporous graphene (NPG) as an ordered covalent array of graphene nanoribbons
(GNRs). Within NPG, the GNRs may be thought of as 1D electronic nanochannels
through which electrons preferentially move, highlighting NPG's potential for
carbon nanocircuitry. However, the {\pi}-conjugated bonds bridging the GNRs
give rise to electronic cross-talk between the individual 1D channels, leading
to spatially dispersing electronic currents. Here, we propose a chemical design
of the bridges resulting in destructive quantum interference, which blocks the
cross-talk between GNRs in NPG, electronically isolating them. Our multiscale
calculations reveal that injected currents can remain confined within a single,
0.7 nm wide, GNR channel for distances as long as 100 nm. The concepts
developed in this work thus provide an important ingredient for the quantum
design of future carbon nanocircuitry