Understanding the Contrast Mechanism in Scanning Tunneling Microscopy (STM) Images of an Intermixed Tetraphenylporphyrin Layer on Ag(111)

Comanici, Karmen; Büchner, Florian; Flechtner, Ken; Lukasczyk, Thomas; Gottfried, J. Michael; Steinrück, Hans‐Peter; Marbach, Hubertus

doi:10.1021/la703263e

Cited by 62 publications

(82 citation statements)

References 32 publications

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“…45 A bright central protrusion, originating from Co atomic states, dominates the appearance of Co-TPP/Ag(111) at low bias voltages (Figure 1a, À0.4 V). 46 At higher negative bias voltages (V b > À0.5 eV), submolecular resolution evidence a 2-fold symmetry of the Co-TPP macrocycle ( Figure 1b). As detailed in a previous study, this contrast is related to an adsorption induced saddle-shape deformation of Co-TPP, where the so-called R-pyr axis dominates the appearance (cf.…”

Section: Resultsmentioning

confidence: 98%

Restoring the Co Magnetic Moments at Interfacial Co-Porphyrin Arrays by Site-Selective Uptake of Iron

et al. 2015

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T he fabrication of addressable, surfacebased arrays comprising single atomic spins and magnetic moments is a key to comprehensively understand magnetic phenomena on the nanoscale, 1À3 and to realize potential sensing, information storage, spintronic or quantum computing devices. 4À7 Recently, the bottom-up assembly of metalÀorganic magnetic layers and architectures on surfaces has attracted considerable interest, given the versatility of molecular building blocks combined with metal centers featuring magnetic moments. 8À10 Prominent results include multicomponent two-dimensional metalÀ organic networks 11,12 or dense-packed arrays of metalÀorganic complexes, 2,13 where unpaired d-or f-electrons contribute to the magnetic moment for transition metal and lanthanide centers, respectively. This selfassembly approach guarantees an exquisite control on the positions and the local coordination sphere of the magnetic centers, comparable to the precise atom positioning achieved by serial manipulation procedures based on low-temperature scanning tunneling microscopy (STM), 14,15 which however are not applicable for large-scale patterning of substrates, a frequent criterion for applications.Commonly, the interaction of molecules and metal centers with the supporting surface affects their electronic and magnetic properties, and tetrapyrrole species have been frequently employed for exemplary investigations in this context. 16 While this complemented by density functional theory (DFT) calculations, evidence a ferromagnetic coupling between the Fe and the Co center concomitant with a complex charge redistribution involving the porphyrin ligand. Thus, we demonstrate an unusual metalloporphyrin coordination geometry that opens pathways to spatially order and engineer magnetic moments in surface-based nanostructures.KEYWORDS: magnetochemistry . magnetic moment . metalloporphyrin . template . scanning tunneling microscopy (STM) . X-ray magnetic circular dichroism (XMCD) . density functional theory (DFT) ARTICLE

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Section: Resultsmentioning

confidence: 98%

Restoring the Co Magnetic Moments at Interfacial Co-Porphyrin Arrays by Site-Selective Uptake of Iron

et al. 2015

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“…For CoTPP on Ag(1 1 1) [286,375,376,[388][389][390], an incommensurate lattice with a square unit cell (14.05 Â 14.05 Å 2 , 901) was observed ( Fig. 22a) [390].…”

Section: Tetraphenylporphyrins and Derivativesmentioning

confidence: 91%

Surface chemistry of porphyrins and phthalocyanines

Gottfried

2015

Surface Science Reports

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583

586

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“…The small number of depressions in the 2D islands under the given measurement condition probably originate from metal-free TTBPBP molecules, which are most likely already present in the Ni-TTBPBP material before evaporation onto the substrate. 33,39 As next step, we analyse the intramolecular conformation of Ni-TTBPBP on Cu(111). Fig.…”

Section: Resultsmentioning

confidence: 99%

Self-assembly and coverage dependent thermally induced conformational changes of Ni(ii)-meso-tetrakis (4-tert-butylphenyl) benzoporphyrin on Cu(111)

Zhang

Lepper

Stark

et al. 2015

Phys. Chem. Chem. Phys.

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A systematic scanning tunnelling microscopy investigation of the self-assembly and of thermally induced conformational changes of Ni(II)-meso-tetrakis (4-tert-butylphenyl) benzoporphyrin (Ni-TTBPBP) onCu (111) is presented. At room temperature, Ni-TTBPBPs diffuse on the surface and self-assemble into ordered islands with well-defined registry to the substrate, with two different azimuthal orientations. The formation of the characteristic supramolecular structure is attributed to van der Waals interactions between the tert-butyl groups. Upon moderate heating, the intramolecular conformation changes irreversibly due to a dehydrogenative intramolecular aryl-aryl coupling reaction. This reaction is coverage dependent, with a lower rate at higher initial coverage; this behaviour is attributed to a stabilization of Ni-TTBPBP in the ordered islands at higher coverage.

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Understanding the Contrast Mechanism in Scanning Tunneling Microscopy (STM) Images of an Intermixed Tetraphenylporphyrin Layer on Ag(111)

Cited by 62 publications

References 32 publications

Restoring the Co Magnetic Moments at Interfacial Co-Porphyrin Arrays by Site-Selective Uptake of Iron

Restoring the Co Magnetic Moments at Interfacial Co-Porphyrin Arrays by Site-Selective Uptake of Iron

Surface chemistry of porphyrins and phthalocyanines

Self-assembly and coverage dependent thermally induced conformational changes of Ni(ii)-meso-tetrakis (4-tert-butylphenyl) benzoporphyrin on Cu(111)

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