Sensing Dipole Fields at Atomic Steps with Combined Scanning Tunneling and Force Microscopy

Park, Jeong Young; Sacha, G. M.; Enăchescu, Marius; Ogletree, D. Frank; Ribeiro, R. A.; Canfield, Paul C.; Jenks, Cynthia J.; Thiel, Patricia A.; Sáenz, Juan José; Salmerón, Miquel

doi:10.1103/physrevlett.95.136802

Cited by 51 publications

(32 citation statements)

References 22 publications

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“…The calculated dipole moments for the adsorbed atom (1:23 D=step atom) and the pyramid tip (1:98 D=step atom; see Ref. [4] for details) broadly agree with the results of previous studies on extended steps at metal surfaces (0:16 À 1 D=step atom [11,12]) and increase with decreasing the coordination of surface atoms [13]. We note that this fundamental property of metal surfaces is difficult to describe within continuum approximations to the tip polarization [14], and remained unaccounted for in some recent models of Kelvin probe microscopy [15].…”

supporting

confidence: 80%

“…The orientation of the tip dipole (its positive pole is pointing to the surface) favors the interaction with the negative surface Cl ion and is enhanced by the additional polarization of the tip and the surface caused by the interaction, in agreement with Ref. [11].…”

supporting

confidence: 74%

“…For common metallic or metal-coated tips (e.g., tungsten [20]), it will point with its positive pole into the vacuum region, i.e., towards the sample surface [11]. In most cases anions are more polarizable than cations and protrude out of the surface plane due to surface rumpling [21].…”

mentioning

confidence: 99%

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Chemical Resolution at Ionic Crystal Surfaces Using Dynamic Atomic Force Microscopy with Metallic Tips

Teobaldi

Lämmle²,

Trevethan

et al. 2011

Phys. Rev. Lett.

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We demonstrate that well prepared and characterized Cr tips can provide atomic resolution on the bulk NaCl(001) surface with dynamic atomic force microscopy in the noncontact regime at relatively large tip-sample separations. At these conditions, the surface chemical structure can be resolved yet tipsurface instabilities are absent. Our calculations demonstrate that chemical identification is unambiguous, because the interaction is always largest above the anions. This conclusion is generally valid for other polar surfaces, and can thus provide a new practical route for straightforward interpretation of atomically resolved images.

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supporting

confidence: 80%

supporting

confidence: 74%

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Chemical Resolution at Ionic Crystal Surfaces Using Dynamic Atomic Force Microscopy with Metallic Tips

Teobaldi

Lämmle²,

Trevethan

et al. 2011

Phys. Rev. Lett.

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“…This was useful to monitor the variation of force during STM imaging. 29,30 In contact AFM mode, the normal force was used for feedback, which yielded topography, while friction force and current were measured simultaneously.…”

Section: Experimental Descriptionmentioning

confidence: 99%

Tribological properties of quasicrystals: Effect of aperiodic versus periodic surface order

et al. 2006

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We investigated the nanoscale tribological properties of a decagonal quasicrystal using a combination of atomic force microscopy and scanning tunneling microscopy in ultrahigh vacuum. This combination permitted a variety of in situ measurements, including atomic-scale structure, friction and adhesion force, tipsample current, and topography. We found that thiol-passivated tips can be used for reproducible studies of the tip-quasicrystal contact while nonpassivated probes adhere irreversibly to the clean quasicrystalline surface causing permanent modifications. The most remarkable results were obtained on the twofold surface of the Al-Ni-Co decagonal quasicrystal where atoms are arranged periodically along the tenfold axis and aperiodically in the perpendicular direction. Strong friction anisotropy was observed on this surface, with high friction along the periodic direction and low friction in the aperiodic direction. We investigated the nanoscale tribological properties of a decagonal quasicrystal using a combination of atomic force microscopy and scanning tunneling microscopy in ultrahigh vacuum. This combination permitted a variety of in situ measurements, including atomic-scale structure, friction and adhesion force, tip-sample current, and topography. We found that thiol-passivated tips can be used for reproducible studies of the tip-quasicrystal contact while nonpassivated probes adhere irreversibly to the clean quasicrystalline surface causing permanent modifications. The most remarkable results were obtained on the twofold surface of the Al-Ni-Co decagonal quasicrystal where atoms are arranged periodically along the tenfold axis and aperiodically in the perpendicular direction. Strong friction anisotropy was observed on this surface, with high friction along the periodic direction and low friction in the aperiodic direction.

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“…[9] Because of the Smoluchowski effect, [10] the redistribution of electrons at step sites creates a local electric dipole, which has been characterized by STM and electrostatic force microscope. [11] The asymmetric electronic structure at the step edges could affect the adsorption and desorption, [12][13][14][15][16][17][18][19] diffusion, [20][21][22][23] and chemical reactivity of molecules. [5,24,25] For example, nucleophilic molecules such as benzene prefer to bind to the electron-poor region at the upper step edges.…”

Section: Introductionmentioning

confidence: 99%

Step‐Mediated Anisotropic Adsorption and Condensation of tert‐Butylamine on Cu(111)

et al. 2010

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Scanning tunneling microscopy (STM) combined with density functional theory (DFT) calculations were applied in studying the anisotropic adsorption and condensation of tert-butylamine (t-BA) molecules in the vicinity of the steps on the Cu(111) surface. The preferential adsorption at the upper step edges and uneven distribution of t-BA in the vicinity of the steps illustrate the asymmetric electronic structure of the surface steps. Our observation demonstrates that the adsorption and diffusion of a polar molecule would be significantly mediated by steps on metal surfaces due to the molecule-step interaction and the intermolecular interactions.

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Sensing Dipole Fields at Atomic Steps with Combined Scanning Tunneling and Force Microscopy

Cited by 51 publications

References 22 publications

Chemical Resolution at Ionic Crystal Surfaces Using Dynamic Atomic Force Microscopy with Metallic Tips

Chemical Resolution at Ionic Crystal Surfaces Using Dynamic Atomic Force Microscopy with Metallic Tips

Tribological properties of quasicrystals: Effect of aperiodic versus periodic surface order

Step‐Mediated Anisotropic Adsorption and Condensation of tert‐Butylamine on Cu(111)

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