Title
Equivalence between p-cyclic quasimonotonicity and p-cyclic monotonicity of affine maps
Date Issued
2015
Access level
open access
Resource Type
journal article
Author(s)
Meza, JAM
Lubin, C
Thoyer, F
Rosales, KAV
Espinoza, AAG
Martin, F
Cousty, J
Publisher(s)
Elsevier Ltd
Abstract
Abstract The fabrication of ultra-sharp tips from carbon fiber (CF), which are mounted on a qPlus probe for combined dynamic scanning tunneling microscopy (STM) and frequency modulation atomic force microscopy (FM-AFM) experiments, is reported. The carbon fiber tips were electrochemically etched in a KOH or NaOH solution, using different electronic devices. CF tips with an apex radius ∼10 nm, as deduced from the measured slopes of the Fowler-Nordheim plots (kR < 70 nm for k ∼ 6), were routinely obtained with a homemade electronic device that controls the intensity of the etching current. Then, these conductive CF tips were also characterized by imaging the 6H-SiC(0 0 0 1) surface covered by an epitaxial graphene layer in ultra-high vacuum (UHV). The lattice of the (63×63) R30 reconstruction was regularly imaged by STM working either in non-oscillating mode or in dynamic mode, which also maps the variations of the force gradient. From these measurements with a constant mean-tunneling-current of 20 pA, it was found that the STM tip suffered variations of the tip/surface force gradient in between 8.25 and 16.50 N/m when it scanned the epitaxial graphene layer on the reconstructed 6H-SiC(0 0 0 1) surface. © 2015 Elsevier Ltd. All rights reserved.
Start page
363
End page
370
Volume
86
Number
9
Language
English
Scopus EID
2-s2.0-84924565690
Source
Carbon
ISSN of the container
0008-6223
Sponsor(s)
José Antonio Morán Meza would also like to acknowledge financial support from the Peru’s National Council of Science and Technology (Concytec), the Réseau Thématique de Recherche Avancée (RTRA-Triangle de la Physique), and the CEA/Direction des Relations Internationales (DRI).
Sources of information: Directorio de Producción Científica