Controlled Atomic Doping of a Single C
            <sub>60</sub>
            Molecule

Yamachika, Ryan; Grobis, M.; Wachowiak, Andre; Crommie, Michael F.

doi:10.1126/science.1095069

Cited by 119 publications

(60 citation statements)

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“…Shifts of molecular states induced by metal-molecule contact have been reported in different systems [4][5][6][7][8][9][10][11][12][13][14], but cumulative shifts by multiple contacts have rarely been reported. To our knowledge, the only example is that in K x C 60 complexes the C 60 states are down shifted cumulatively due to stepwise charge transfer (each attached K atom donates $0:6e to the C 60 host) [10]. DFT calculations conclude that there is no significant charge transfer between the TPyB molecule and the coordinated Cu atoms (less than 0.1 electrons from Bader charge analysis), thus excluding that the observed energy level shifts are caused by charging effects.…”

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confidence: 99%

“…Scanning tunneling microscopy and spectroscopy (STM-STS) have been used to address this challenging problem owing to their capability of resolving geometric details of molecule-metal contacts and simultaneously measuring the single-molecule electronic properties. These studies revealed in great detail that the molecular frontier orbitals are modulated when the molecules are coupled to metal atoms or a metal substrate [4][5][6][7][8][9][10][11][12][13][14]. So far, most of these studies focused on molecules coupled to one or at most two metal contacts.…”

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confidence: 99%

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Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

et al. 2013

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We use cryogenic scanning tunneling microscopy and spectroscopy and density-functional theory calculations to inspect the modulation of electronic states of aromatic molecules. The molecules are selfassembled on a Cu(111) surface forming molecular networks in which the molecules are in different contact configurations, including laterally coupled to different numbers of coordination bonds and vertically adsorbed at different heights above the substrate. We quantitatively analyze the molecular states and find that a delocalized empty molecular state is modulated by these multiple contacts in a cooperative manner: its energy is down shifted by $0:16 eV for each additional lateral contact and by $0:1 eV as the vertical molecule-surface distance is reduced by 0.1 Å in the physisorption regime. We also report that in a moleculemetal-molecule system the bridging metal can mediate the electronic states of the two molecules. DOI: 10.1103/PhysRevLett.110.046802 PACS numbers: 73.20.Hb, 68.37.Ef, 73.63.Rt, 85.65.+h The electronic structure of a molecule is subject to the coupling of the molecule with its environment [1,2]. A thorough understanding of this issue is of great importance in the field of molecular electronics considering that the characteristics of molecular devices are determined by the molecular electronic structures and their contacts [3]. For example, a metal-molecule interface may strongly modify the molecular orbitals, and consequently, molecular conductance [3]. As one of the ultimate goals of molecular electronics is to realize single-molecule devices, wherein single molecules are connected to electrodes, one needs to understand how molecule-electrode coupling affects the molecular electronic structures at the level of individual molecules. Scanning tunneling microscopy and spectroscopy (STM-STS) have been used to address this challenging problem owing to their capability of resolving geometric details of molecule-metal contacts and simultaneously measuring the single-molecule electronic properties. These studies revealed in great detail that the molecular frontier orbitals are modulated when the molecules are coupled to metal atoms or a metal substrate [4][5][6][7][8][9][10][11][12][13][14]. So far, most of these studies focused on molecules coupled to one or at most two metal contacts. In future single-molecule devices, however, the molecules will be mostly connected to multiple electrodes, for example, to source, drain and gate electrodes in a field-effect transistor [15][16][17][18][19][20]. It is highly desirable to study individual molecules that are coupled to multiple metal contacts.In this Letter, we report on a combined study with low-temperature STM-STS and density-functional theory (DFT) of the electronic structures of extended aromatic molecules that are coupled with multiple metal contacts. The molecules are attached laterally to two or three neighboring molecules through metal-ligand coordination bonds and vertically to a metal surface at different distance. These parameters can be se...

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Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

et al. 2013

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“…Photoemission spectra obtained from an increasingly K-doped monolayer of C 60 on Ag(111) shows a triply degenerate LUMO progressively filling with electrons, but no splitting [17]. In contrast, a study [30] using STM techniques to sequentially K-dope an individual C 60 molecule on a Ag(001) surface showed a clear splitting in the dI/ dV spectrum of the undoped C 60 , as shown in Fig. 7.…”

Section: Monolayersmentioning

confidence: 95%

“…Of particular merit is the work of Crommie and co-workers who, in a series of papers [30,5,38,39], have recorded some very intriguing images and spectra of a series of doped C 60 molecules. In one experiment [on Ag(111)], these workers were able to use the STM tip to progressively attach/detach potassium atoms to individual C 60 molecules and subsequently record the scanning tunnelling spectroscopy data shown in Fig.…”

Section: Stm Imaging Of Fullerenes: An Overviewmentioning

confidence: 99%

Jahn–Teller Effects in Molecules on Surfaces with Specific Application to C60

Hands

Dunn

Rawlinson

et al. 2009

Springer Series in Chemical Physics

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Abstract Scanning tunnelling microscopy (STM) is capable of imaging molecules adsorbed onto surfaces with sufficient resolution as to permit intramolecular features to be discerned. Therefore, imaging molecules subject to the Jahn-Teller (JT) effect could, in principle, yield valuable information about the vibronic coupling responsible for the JT effect. However, such an application is not without its complications. For example, the JT effect causes subtle, dynamic distortions of the molecule; but how will this dynamic picture be affected by the host surface? And what will actually be imaged by the rather slow STM technique? Our aim here is to present a systematic investigation of the complications inherent in JT-related STM studies, to seek out possible JT signatures in such images and to guide further imaging towards identification and quantification of JT effects in molecules on surfaces. In particular, we consider the case of surface-adsorbed C 60 ions because of their propensity to exhibit JT effects, their STM-friendly size and because a better understanding of the vibronic effects within these ions may be important for realisation of their potential application as superconductors.

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“…Fullerene's large electron affinity is known to yield to electron transfer into C 60 when adsorbed on metallic substrates. The actual number of doped electrons depends on the substrate[4], but may also be controlled by attaching alkali atoms to the molecule [5]. In this case a variety of conductance behavior has been reported depending on the number of K-atoms attached to C 60 [5], ranging from Kondo-like resonances to Fano-like anti-resonances.…”

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Surprises in the Phase Diagram of an Anderson Impurity Model for a Single C60n- Molecule

Leo

Fabrizio

2005

Phys. Rev. Lett.

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We find by Wilson numerical renormalization group and conformal field theory that a three-orbital Anderson impurity model for a C n− 60 molecule has a very rich phase diagram which includes non-Fermi-liquid stable and unstable fixed points with interesting properties, most notably high sensitivity to doping n. We discuss the implications of our results to the conductance behavior of C60-based single-molecule transistor devices. PACS numbers: 71.10.Hf,72.15.Qm, The characteristic behavior of an Anderson impurity model (AIM) emerges often unexpectedly in physical contexts which are apparently faraway from magnetic alloys. The typical example is the conductance behavior of nano-scale devices, e.g. quantum dots and single-molecule transistors (SMT), where Kondo-assisted tunneling may lead to nearly perfect transmission at zero bias in spite of a large charging energy [1]. Usually the two conduction leads are bridged by a single quantum dot or molecular level, which therefore behaves effectively as a one-orbital AIM. Less common is the case when several levels happen to be nearby degenerate thus realizing in practice a multi-orbital AIM. This may be achieved for instance in SMTs built with high-symmetry molecules. Recently a zero-bias anomaly has been reported for a C 60 based SMT[2], which has been proven to be of the Kondo-type by its splitting under the action of a magnetic field or magnetic leads[3]. Fullerene's large electron affinity is known to yield to electron transfer into C 60 when adsorbed on metallic substrates. The actual number of doped electrons depends on the substrate[4], but may also be controlled by attaching alkali atoms to the molecule [5]. In this case a variety of conductance behavior has been reported depending on the number of K-atoms attached to C 60 [5], ranging from Kondo-like resonances to Fano-like anti-resonances.Motivated by this opportunity, in this Letter we study the behavior of an AIM for C n− 60 by Wilson Numerical Renormalization Group (NRG) [6] and Conformal Field Theory (CFT) [7]. We obtain a phase diagram which includes Fermiand non-Fermi-liquid phases, with a doping dependence qualitatively in agreement with experiments. In particular we find a Kondo-like zero-bias anomaly for doping n = 1, likely the case of C 60 on Au[4], as found in Refs. [2,3]. For n = 2, which should correspond to pure or slightly K-doped C 60 on Ag[4], we predict instead a conductance-minimum at zerobias, compatible with actual observations [5]. Finally, for n = 3 we find a conductance minimum with a non-analytic voltage behavior G(V ) − G(0) ∼ |V | 2/5 . The LUMO's of C 60 are three-fold degenerate t 1u orbitals [8]. The electron-electron interaction acts as if these orbitals were effectively p-orbitals. Therefore the Coulomb energy of a C n− 60 molecule with n valence electrons into a configuration with total spin S and angular momentum L is. The reference valency, n 0 , is controlled in SMTs by the gate voltage, the metal substrate and the alkali doping. The Coulomb exchange, J > 0, favoring high-de...

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Controlled Atomic Doping of a Single C ₆₀ Molecule

Cited by 119 publications

References 19 publications

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

Jahn–Teller Effects in Molecules on Surfaces with Specific Application to C60

Surprises in the Phase Diagram of an Anderson Impurity Model for a Single C60n- Molecule

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Controlled Atomic Doping of a Single C 60 Molecule

Cited by 119 publications

References 19 publications

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

Jahn–Teller Effects in Molecules on Surfaces with Specific Application to C60

Surprises in the Phase Diagram of an Anderson Impurity Model for a Single C60n- Molecule

Contact Info

Product

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Controlled Atomic Doping of a Single C ₆₀ Molecule