Electronic and magnetic properties of molecule-metal interfaces: Transition-metal phthalocyanines adsorbed on Ag(100)

Mugarza, Aitor; Robles, Roberto; Krull, Cornelius; Korytár, Richard; Lorente, Nicolás; Gambardella, Pietro

doi:10.1103/physrevb.85.155437

Cited by 247 publications

(363 citation statements)

References 90 publications

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“…In this situation, one expects a resonance to appear in the differential conductance spectra at zero bias, similar to that in the Kondo regime but characterized by a larger width [36,37]. It is interesting to note that the small hybridization with the surface prevents the finite spin in the d xy orbital from quenching, in contrast with the scenario reported in related systems [38,39]. This allows for a many-body correlated state to emerge.…”

mentioning

confidence: 42%

Reversible Change of the Spin State in a Manganese Phthalocyanine by Coordination of CO Molecule

et al. 2012

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We show that the magnetic state of individual manganese phthalocyanine (MnPc) molecules on a Bi(110) surface is modified when the Mn2þ center coordinates to CO molecules adsorbed on top. Using scanning tunneling spectroscopy we identified this change in magnetic properties from the broadening of a Kondo-related zero-bias anomaly when the CO-MnPc complex is formed. The original magnetic state can be recovered by selective desorption of individual CO molecules. First principles calculations show that the CO molecule reduces the spin of the adsorbed MnPc from S ¼ 1 to S ¼ 1=2 and strongly modifies the respective screening channels, driving a transition from an underscreened Kondo state to a state of mixed valence. DOI: 10.1103/PhysRevLett.109.147202 PACS numbers: 75.20.Hr, 68.37.Ef, 82.37.Gk, 68.43.Bc Control over the magnetic moment of a molecule and its interaction with a substrate is a key issue in the emerging field of molecular spintronics [1]. In metal-phthalocyanines and metal-porphyrins the metal center is usually coordinatively unsaturated and presents a local reactive site, which opens a unique possibility of controlling the magnetic moment in situ by external chemical stimuli [2][3][4][5][6][7][8]. The axial coordination of small molecules like CO, NO or O 2 to those complexes substantially alters their electronic properties, which has led to a successful implementation of phthalocyanines and porphyrins in gas sensors [9,10]. Studies specifically addressing the magnetic state are, however, scarce. Only recently it has been shown that the attachment of a NO molecule to a cobalt-tetraphenylporphyrin (CoTPP) quenches its spin due to the oxidation process [6]. The general picture is however more complicated, as the chemical bond to the reactant molecule causes the redistribution of charge in the d orbitals of the metal center and modifies the ligand field of the metal ion. This has critical consequences for the magnetic ground state of the complex [7,8]. On metal surfaces, the formation of a new ligand bond may additionally alter the hybridization of molecular and substrate states, thus affecting the electronic and magnetic coupling of the metal ion to the substrate [3][4][5]. Understanding the response of these effects to the change in chemical coordination is crucial to gain full control over the functionality of the magnetic system.Here, we show that the magnetic moment of a manganese phthalocyanine (MnPc) molecule [see Fig. 1(a)] on a Bi(110) surface is reduced when coordinated to a CO molecule. Using a combination of a low temperature scanning tunneling microscopy (STM) and density functional theory (DFT) we find, first, that the spin of the MnPc molecule is reduced from S ¼ 3=2 to S ¼ 1 upon adsorption and, second, that CO further reduces the spin of the MnPc from S ¼ 1 to S ¼ 1=2. The change in the magnetic ground state upon CO attachment is detected by the broadening of a characteristic zero-bias anomaly (ZBA). We interpret this broadening as a transition from a Kondo regime, for the bare MnPc on...

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confidence: 42%

Reversible Change of the Spin State in a Manganese Phthalocyanine by Coordination of CO Molecule

et al. 2012

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“…At the SCBA level 20 (15) with N λ giving the boson occupation numbers N λ = f BE ( λ /kT ) and N λ = N λ + 1. We have further employed the short notation n…”

Section: B Isolated Leads In Equilibriummentioning

confidence: 99%

“…Within the context of the STM, this technique is denoted as inelastic electron tunneling spectroscopy (STM-IETS) and is extensively employed to characterize the molecule's vibrational spectra. [9][10][11][12][13][14][15] From the theoretical side, a wealth of formalisms dealing with the inelastic transport have been developed in parallel to these delicate experiments. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The earliest models for IETS employed a multiple scattering formalism (multichannels) with simplified semiempirical Hamiltonians 16 or a Tersoff-Hamman-(TH-) type approach.…”

Section: Introductionmentioning

confidence: 99%

Lowest order in inelastic tunneling approximation: Efficient scheme for simulation of inelastic electron tunneling data

2013

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We have developed an efficient and accurate formalism which allows the simulation at the ab initio level of inelastic electron tunneling spectroscopy data under a scanning tunneling microscope setup. It exploits fully the tunneling regime by carrying out the structural optimization and vibrational mode calculations for surface and tip independently. The most relevant interactions in the inelastic current are identified as the inelastic tunneling terms, which are taken into account up to lowest order, while all other inelastic contributions are neglected. As long as the system is under tunneling regime conditions and there is no physisorbed molecule on the surface or tip apex, this lowest order in inelastic tunneling (LOIT) approach reduces drastically the computational cost compared to related approaches while maintaining a good accuracy. Adopting the wide-band limit for both tip and surface further reduces calculation times significantly, and is shown to give similar results to when the full energy dependence of the Green's functions is taken into account. The LOIT is applied to the Cu(111) + CO system probed by a clean and a CO contaminated tip to find good agreement with previous works. Different parameters involved in the calculations such as basis sets, k sampling, tip-sample distance, or temperature, among others, are discussed in detail.

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“…However, it is well known that van der Waals interaction is a large component in the binding of large organic molecules such as phthalocyanines on noble-metal surfaces. 37 In order to assess the accuracy of the LDA PES, we repeated the calculations just for the φ = 0…”

Section: Density Functional Theory Descriptionmentioning

confidence: 99%

Tunneling electron induced rotation of a copper phthalocyanine molecule on Cu(111)

et al. 2013

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The rates of a hindered molecular rotation induced by tunneling electrons are evaluated using scattering theory within the sudden approximation. Our approach explains the excitation of copper phthalocyanine molecules (CuPc) on Cu(111) as revealed in a recent measurement of telegraph noise in a scanning tunneling microscopy experiment [Schaffert et al., Nat. Mater. 12, 223 (2013)]. A complete explanation of the experimental data is performed by computing the geometry of the adsorbed system, its electronic structure, and the energy transfer between tunneling electrons and the molecule's rotational degree of freedom. The results unambiguously show that tunneling electrons induce a frustrated rotation of the molecule. In addition, the theory determines the spatial distribution of the frustrated rotation excitation, confirming the striking dominance of two out of four molecular lobes in the observed excitation process. This lobe selectivity is attributed to the different hybridizations with the underlying substrate.

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Electronic and magnetic properties of molecule-metal interfaces: Transition-metal phthalocyanines adsorbed on Ag(100)

Cited by 247 publications

References 90 publications

Reversible Change of the Spin State in a Manganese Phthalocyanine by Coordination of CO Molecule

Reversible Change of the Spin State in a Manganese Phthalocyanine by Coordination of CO Molecule

Lowest order in inelastic tunneling approximation: Efficient scheme for simulation of inelastic electron tunneling data

Tunneling electron induced rotation of a copper phthalocyanine molecule on Cu(111)

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