Multi-orbital non-crossing approximation from maximally localized Wannier functions: the Kondo signature of copper phthalocyanine on Ag(100)

Korytár, Richard; Lorente, Nicolás

doi:10.1088/0953-8984/23/35/355009

Cited by 40 publications

(64 citation statements)

References 78 publications

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“…In this section we address this important topic and provide a solution for this conundrum. [54][55][56][57]59,62], computed using the code WANNIER90, as described in Ref. [57].…”

Section: Connection With the Spin Modelsmentioning

confidence: 99%

Electronic properties of transition metal atoms onCu2N/Cu(100)

2015

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We study the nature of spin excitations of individual transition metal atoms (Ti, V, Cr, Mn, Fe, Co, and Ni) deposited on a Cu 2 N/Cu(100) surface using both spin-polarized density functional theory (DFT) and exact diagonalization of an Anderson model derived from DFT. We use DFT to compare the structural, electronic, and magnetic properties of different transition metal adatoms on the surface. We find that the average occupation of the transition metal d shell, main contributor to the magnetic moment, is not quantized, in contrast with the quantized spin in the model Hamiltonians that successfully describe spin excitations in this system. In order to reconcile these two pictures, we build a zero bandwidth multi-orbital Anderson Hamiltonian for the d shell of the transition metal hybridized with the p orbitals of the adjacent nitrogen atoms, by means of maximally localized Wannier function representation of the DFT Hamiltonian. The exact solutions of this model have quantized total spin, without quantized charge at the d shell. We propose that the quantized spin of the models actually belongs to many-body states with two different charge configurations in the d shell, hybridized with the p orbital of the adjacent nitrogen atoms. This scenario implies that the measured spin excitations are not fully localized at the transition metal.

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“…In this section we address this important topic and provide a solution for this conundrum. [54][55][56][57]59,62], computed using the code WANNIER90, as described in Ref. [57].…”

Section: Connection With the Spin Modelsmentioning

confidence: 99%

Electronic properties of transition metal atoms onCu2N/Cu(100)

2015

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“…In this direction a number of different ab initio based approaches were suggested. [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] It should be noted that many-body calculations usually require sophisticated analytical and numerical methods and can be very time consuming. Hence, the methods of transport theory cannot usually be applied directly to large realistic systems; instead a combined approach is preferable where an effective model takes only the states predominantly participating in transport into account.…”

Section: Introductionmentioning

confidence: 99%

“…Progress in this direction recently was achieved in applications to Coulomb blockade phenomena, 37 correlated transport through atomic wires, 38,39 many-body interference, 40 and the Kondo effect. [44][45][46][47][48] Besides, Coulomb blockade phenomena in benzene and benzenedithiol junctions were also considered on the basis of semiempirical atomistic models. [51][52][53] However, a systematic ab initio based many-body theory of molecular transport is still lacking.…”

Section: Introductionmentioning

confidence: 99%

Many-body localized molecular orbital approach to molecular transport

et al. 2013

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An ab initio based theoretical approach to describe nonequilibrium many-body effects in molecular transport is developed. We introduce a basis of localized molecular orbitals and formulate the many-body model in this basis. In particular, the Hubbard-Anderson Hamiltonian is derived for single-molecule junctions with intermediate coupling to the leads. As an example we consider a benzenedithiol junction with gold electrodes. An effective few-level model is obtained from which spectral and transport properties are computed and are analyzed. Electron-electron interaction crucially affects transport and induces multiscale Coulomb blockade at low biases. At large bias, transport through asymmetrically coupled molecular edge states results in the occurrence of "anomalous" conductance features, i.e., of peaks with unexpectedly large/small height or even not located at the expected resonance energies.

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“…The result is that the two unpaired spins are screened via Kondo screening channels with a very different energy scale and, thus, Kondo temperature [17]. Such a scheme suggests an underscreened spin if the experimental temperature lies between the Kondo temperatures of each screening channels [30,31].…”

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confidence: 99%

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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Multi-orbital non-crossing approximation from maximally localized Wannier functions: the Kondo signature of copper phthalocyanine on Ag(100)

Cited by 40 publications

References 78 publications

Electronic properties of transition metal atoms onCu2N/Cu(100)

Electronic properties of transition metal atoms onCu2N/Cu(100)

Many-body localized molecular orbital approach to molecular transport

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

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