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We employ room-temperature ultrahigh vacuum scanning tunneling microscopy (UHV STM) and {em ab-initio} calculations to study graphene flakes that were adsorbed onto the Si(111)$-$7$times$7 surface. The characteristic 7$times$7 reconstruction of this semiconductor substrate can be resolved through graphene at all scanning biases, thus indicating that the atomistic configuration of the semiconducting substrate is not altered upon graphene adsorption. Large-scale {em ab-initio} calculations confirm these experimental observations and point to a lack of chemical bonding among interfacial graphene and silicon atoms. Our work provides insight into atomic-scale chemistry between graphene and highly-reactive surfaces, directing future passivation and chemical interaction work in graphene-based heterostructures.
We demonstrate that it is possible to mechanically exfoliate graphene under ultra high vacuum conditions on the atomically well defined surface of single crystalline silicon. The flakes are several hundred nanometers in lateral size and their optical
We report an experimental refinement of the local charge density at the Si (111) 7x7 surface utilizing a combination of x-ray and high energy electron diffraction. By perturbing about a bond-centered pseudoatom model, we find experimentally that the
This paper has been withdrawn by first author KM Seemann.
We propose a natural two-speed model for the phase dynamics of Si(111) 7$times$7 phase transition to high temperature unreconstructed phase. We formulate the phase dynamics by using phase-field method and adaptive mesh refinement. Our simulated resul
We report scanning tunneling microscopy observations of Ge deposited on the Si(111)-7x7 surface for a sequence of sub-monolayer coverages. We demonstrate that Ge atoms replace so-called Si adatoms. Initially, the replacements are random, but distinct