Nanoscale periodic modulations on sodium chloride surface revealed by tuning fork atomic force microscopy

Abstract

The sodium chloride surface is one of the most common platforms for the study of catalysts, thin film growth, and atmospheric aerosols. Here we report a nanoscale periodic modulation pattern on the surface of a cleaved NaCl single crystal, revealed by non-contact atomic force microscopy with a tuning fork sensor. The surface pattern shows two orthogonal domains, extending over the entire cleavage surface. The spatial modulations exhibit a characteristic period of 5.4 nm, along <110> crystallographic directions of the NaCl. The modulations are robust in vacuum, not affected by the tip-induced electric field or gentle annealing (<300 °C); however, they are eliminated after exposure to water and an atomically flat surface can be recovered by subsequent thermal annealing after water exposure. A strong electrostatic charging is revealed on the cleavage surface which may facilitate the formation of the observed metastable surface reconstruction.

Computational Search for Novel Hard Chromium-Based Materials

“…This phase could be considered as a possible material for isolation of single layer of Cr 2 N using micromechanical cleavage. 69,70 Newly predicted CrN 4 is found in two forms, with space groups 𝑅3𝑐 and 𝐶2/𝑚; their structures are shown in Fig. 3b.…”

“…Another phase of Cr 2 N with space group P 6 3 / mmc has a layered structure and is isostructural to layered transition metal dichalcogenides (TMDCs), shown in Figure b. This phase could be considered as a possible material for isolation of a single layer of Cr 2 N using micromechanical cleavage. , Newly predicted CrN 4 is found in two forms, with space groups R 3 c and C 2/ m ; their structures are shown in Figure b. Detailed structural parameters and energies relative to the convex hull (see Figure c) of considered phases are summarized in Table .…”

Adsorption of PTCDA and C60 on KBr(001): electrostatic interaction versus electronic hybridization

“…KBr(001) [24][25][26][27][28][29][30][31][32] or NaCl(001). 10,11,16,21,31,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] However, few efforts have been made to examine the role of insulating crystalline surfaces in the molecular overlayers, especially in terms of the electronic structure. Insulator surfaces are typically considered to have little to no effect on the molecular overlayers, nevertheless, a clear physical picture of how molecule-substrate electronic hybridization is suppressed on insulators has yet to be reported.…”

Flexible and modular virtual scanning probe microscope

“…In Fig. 8(a) we show the simulated image for NaCl which was constructed from a force field previously created by us [28] (for simulation parameters see the figure caption). When comparing this image with an experimental obtained image (Fig.…”