arXiv subjects

Carlos J. Arguello

Publications and source records attributed to Carlos J. Arguello.

2 recordsLinked to original sources

arXiv2014

Experimental evidence for a Bragg glass density wave phase in a transition-metal dichalcogenide

Analysis of the spatial dependence of current-voltage characteristics obtained from scanning tunneling microscopy experiments indicates that the charge density wave (CDW) occurring in NbSe$_2$ is subject to locally strong pinning by a non-negligible density of defects, but that on the length scales accessible in this experiment the material is in a "Bragg glass" phase where dislocations and anti-dislocations occur in bound pairs and free dislocations are not observed. A Landau theory-based analysis is presented showing how a strong local modulation may produce only a weak long range effect on the CDW phase.

cond-mat.dis-nn↗

arXiv2011

Visualizing Individual Nitrogen Dopants in Monolayer Graphene

In monolayer graphene, substitutional doping during growth can be used to alter its electronic properties. We used scanning tunneling microscopy (STM), Raman spectroscopy, x-ray spectroscopy, and first principles calculations to characterize individual nitrogen dopants in monolayer graphene grown on a copper substrate. Individual nitrogen atoms were incorporated as graphitic dopants, and a fraction of the extra electron on each nitrogen atom was delocalized into the graphene lattice. The electronic structure of nitrogen-doped graphene was strongly modified only within a few lattice spacings of the site of the nitrogen dopant. These findings show that chemical doping is a promising route to achieving high-quality graphene films with a large carrier concentration.

cond-mat.mtrl-sci↗