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Žitko R, Blesio GG, Manuel LO, Aligia AA. Iron phthalocyanine on Au(111) is a "non-Landau" Fermi liquid. Nat Commun 2021; 12:6027. [PMID: 34654828 PMCID: PMC8521586 DOI: 10.1038/s41467-021-26339-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 09/28/2021] [Indexed: 11/24/2022] Open
Abstract
The paradigm of Landau’s Fermi liquid theory has been challenged with the finding of a strongly interacting Fermi liquid that cannot be adiabatically connected to a non-interacting system. A spin-1 two-channel Kondo impurity with anisotropy D has a quantum phase transition between two topologically different Fermi liquids with a peak (dip) in the Fermi level for D < Dc (D > Dc). Extending this theory to general multi-orbital problems with finite magnetic field, we reinterpret in a unified and consistent fashion several experimental studies of iron phthalocyanine molecules on Au(111) that were previously described in disconnected and conflicting ways. The differential conductance shows a zero-bias dip that widens when the molecule is lifted from the surface (reducing the Kondo couplings) and is transformed continuously into a peak under an applied magnetic field. We reproduce all features and propose an experiment to induce the topological transition. Single molecules on metal surfaces are paradigmatic systems for the study of many-body phenomena. Here, the authors show that several spectroscopic experiments on iron phthalocyanine on Au(111) surface can be described in a unified way in terms of a strongly interacting topologically non-trivial (non-Landau) Fermi liquid.
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Affiliation(s)
- R Žitko
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia. .,Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000, Ljubljana, Slovenia.
| | - G G Blesio
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.,Instituto de Física Rosario (CONICET) and Universidad Nacional de Rosario, Bv. 27 de Febrero 210 bis, 2000, Rosario, Argentina
| | - L O Manuel
- Instituto de Física Rosario (CONICET) and Universidad Nacional de Rosario, Bv. 27 de Febrero 210 bis, 2000, Rosario, Argentina
| | - A A Aligia
- Instituto de Nanociencia y Nanotecnología CNEA-CONICET, Centro Atómico Bariloche and Instituto Balseiro, 8400, Bariloche, Argentina
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2
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Wang Y, Li X, Yang J. Spin-flip excitations induced by dehydrogenation in a magnetic single-molecule junction. J Chem Phys 2019; 151:224704. [DOI: 10.1063/1.5129288] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Yu Wang
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Xiaoguang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Jinlong Yang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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3
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Roura-Bas P, Güller F, Tosi L, Aligia AA. Destructive quantum interference in transport through molecules with electron-electron and electron-vibration interactions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:465602. [PMID: 31357183 DOI: 10.1088/1361-648x/ab3684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We study the transport through a molecular junction exhibiting interference effects. We show that these effects can still be observed in the presence of molecular vibrations if Coulomb repulsion is taken into account. In the Kondo regime, the conductance of the junction can be changed by several orders of magnitude by tuning the levels of the molecule, or displacing a contact between two atoms, from nearly perfect destructive interference to values of the order of 2e 2/h expected in Kondo systems. We also show that this large conductance change is robust for reasonable temperatures and voltages for symmetric and asymmetric tunnel couplings between the source-drain electrodes and the molecular orbitals. This is relevant for the development of quantum interference effect transistors based on molecular junctions.
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Affiliation(s)
- P Roura-Bas
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, CONICET, 8400 Bariloche, Argentina
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4
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Fernández J, Roura-Bas P, Camjayi A, Aligia AA. Two-stage three-channel Kondo physics for an FePc molecule on the Au(1 1 1) surface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:374003. [PMID: 30095081 DOI: 10.1088/1361-648x/aad973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We study an impurity Anderson model to describe an iron phthalocyanine (FePc) molecule on Au(1 1 1), motivated by previous results of scanning tunneling spectroscopy (STS) and theoretical studies. The model hybridizes a spin doublet consisting in one hole at the [Formula: see text] orbital of iron and two degenerate doublets corresponding to one hole either in the 3d xz or in the 3d yz orbital (called π orbitals) with two degenerate Hund-rule triplets with one hole in the 3d z orbital and another one in a π orbital. We solve the model using a slave-boson mean-field approximation (SBMFA). For reasonable parameters we can describe very well the observed STS spectrum between sample bias -60 mV to 20 mV. For these parameters the Kondo effect takes place in two stages, with different energy scales [Formula: see text] corresponding to the Kondo temperatures related with the hopping of the z 2 and π orbitals respectively. There is a strong interference between the different channels and the Kondo temperatures, particularly the lowest one is strongly reduced compared with the value in the absence of the competing channel.
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Affiliation(s)
- J Fernández
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, CONICET 8400 Bariloche, Argentina
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5
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Gaudenzi R, de Bruijckere J, Reta D, Moreira IDR, Rovira C, Veciana J, van der Zant HSJ, Burzurí E. Redox-Induced Gating of the Exchange Interactions in a Single Organic Diradical. ACS NANO 2017; 11:5879-5883. [PMID: 28494146 PMCID: PMC5492214 DOI: 10.1021/acsnano.7b01578] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 05/11/2017] [Indexed: 05/21/2023]
Abstract
Embedding a magnetic electroactive molecule in a three-terminal junction allows for the fast and local electric field control of magnetic properties desirable in spintronic devices and quantum gates. Here, we provide an example of this control through the reversible and stable charging of a single all-organic neutral diradical molecule. By means of inelastic electron tunnel spectroscopy we show that the added electron occupies a molecular orbital distinct from those containing the two radical electrons, forming a spin system with three antiferromagnetically coupled spins. Changing the redox state of the molecule therefore switches on and off a parallel exchange path between the two radical spins through the added electron. This electrically controlled gating of the intramolecular magnetic interactions constitutes an essential ingredient of a single-molecule [Formula: see text] quantum gate.
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Affiliation(s)
- Rocco Gaudenzi
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
| | - Joeri de Bruijckere
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
| | - Daniel Reta
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain
| | - Ibério de
P. R. Moreira
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain
| | - Concepció Rovira
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC) and CIBER-BBN, Campus de la UAB, 08193, Bellaterra, Spain
| | - Jaume Veciana
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC) and CIBER-BBN, Campus de la UAB, 08193, Bellaterra, Spain
| | - Herre S. J. van der Zant
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
| | - Enrique Burzurí
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
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6
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Barral MA, Di Napoli S, Blesio G, Roura-Bas P, Camjayi A, Manuel LO, Aligia AA. Kondo behavior and conductance through 3d impurities in gold chains doped with oxygen. J Chem Phys 2017. [DOI: 10.1063/1.4973982] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. A. Barral
- Dpto de Física de la Materia Condensada, GIyA-CNEA, Avenida General Paz 1499, 1650 San Martín, Provincia de Buenos Aires, Argentina and CONICET, 1033 CABA, Argentina
| | - S. Di Napoli
- Dpto de Física de la Materia Condensada, GIyA-CNEA, Avenida General Paz 1499, 1650 San Martín, Provincia de Buenos Aires, Argentina and CONICET, 1033 CABA, Argentina
| | - G. Blesio
- Instituto de Física Rosario, Facultad de Ciencias Exactas, Ingeniería y Agrimensura, Universidad Nacional de Rosario, CONICET, Bv. 27 de Febrero 210 bis, 2000 Rosario, Argentina
| | - P. Roura-Bas
- Dpto de Física de la Materia Condensada, GIyA-CNEA, Avenida General Paz 1499, 1650 San Martín, Provincia de Buenos Aires, Argentina and CONICET, 1033 CABA, Argentina
| | - A. Camjayi
- Departamento de Física, FCEyN, Universidad de Buenos Aires and IFIBA, Pabellón I, Ciudad Universitaria, CONICET, 1428 CABA, Argentina
| | - L. O. Manuel
- Instituto de Física Rosario, Facultad de Ciencias Exactas, Ingeniería y Agrimensura, Universidad Nacional de Rosario, CONICET, Bv. 27 de Febrero 210 bis, 2000 Rosario, Argentina
| | - A. A. Aligia
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, CONICET, 8400 Bariloche, Argentina
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7
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Gaudenzi R, Misiorny M, Burzurí E, Wegewijs MR, van der Zant HSJ. Transport mirages in single-molecule devices. J Chem Phys 2017. [DOI: 10.1063/1.4975767] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- R. Gaudenzi
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - M. Misiorny
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, 412 96 Göteborg, Sweden
- Faculty of Physics, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - E. Burzurí
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - M. R. Wegewijs
- Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT, 52056 Aachen, Germany
- Institute for Theory of Statistical Physics, RWTH Aachen, 52056 Aachen, Germany
| | - H. S. J. van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
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8
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Tosi L, Roura-Bas P, Aligia AA. Restoring the SU(4) Kondo regime in a double quantum dot system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:335601. [PMID: 26235364 DOI: 10.1088/0953-8984/27/33/335601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We calculate the spectral density and occupations of a system of two capacitively coupled quantum dots, each one connected to its own pair of conducting leads, in a regime of parameters in which the total couplings to the leads for each dot Γ(i) are different. The system has been used recently to perform pseudospin spectroscopy by controlling independently the voltages of the four leads. For an odd number of electrons in the system, equal coupling to the leads Γ1 = Γ2, equal dot levels E1 = E2 and sufficiently large interdot repulsion U12 the system lies in the SU(4) symmetric point of spin and pseudospin degeneracy in the Kondo regime. In the more realistic case Γ1 ≠ Γ2, pseudospin degeneracy is broken and the symmetry is reduced to SU(2). Nevertheless, we find that the essential features of the SU(4) symmetric case are recovered by appropriately tuning the level difference δ = E2 - E1. After this tuning, the system behaves as an SU(4) Kondo one at low energies. Our results are relevant for experiments which look for signatures of SU(4) symmetry in the Kondo regime of similar systems.
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Affiliation(s)
- L Tosi
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, 8400 Bariloche, Argentina
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9
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Cleuziou JP, N'Guyen NV, Florens S, Wernsdorfer W. Interplay of the Kondo effect and strong spin-orbit coupling in multihole ultraclean carbon nanotubes. PHYSICAL REVIEW LETTERS 2013; 111:136803. [PMID: 24116802 DOI: 10.1103/physrevlett.111.136803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Indexed: 06/02/2023]
Abstract
We report on cotunneling spectroscopy magnetoconductance measurements of multihole ultraclean carbon nanotube quantum dots in the SU(4) Kondo regime with strong spin-orbit coupling. Successive shells show a gradual weakening of the Kondo effect with respect to the spin-orbital splittings, leading to an evolution from SU(4) to SU(2) symmetry with a suppressed conductance at half-shell filling. The extracted energy level spectrum, overall consistent with negligible disorder in the nanotube, shows in the half filled case large renormalizations due to Coulombian effects.
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Affiliation(s)
- J P Cleuziou
- Institut Néel, CNRS and Université Grenoble Alpes, BP 166, F-38042 Grenoble, France
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10
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Di Napoli S, Weichselbaum A, Roura-Bas P, Aligia AA, Mokrousov Y, Blügel S. Non-Fermi-liquid behavior in transport through Co-doped Au chains. PHYSICAL REVIEW LETTERS 2013; 110:196402. [PMID: 23705724 DOI: 10.1103/physrevlett.110.196402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Indexed: 06/02/2023]
Abstract
We calculate the conductance as a function of temperature G(T) through Au monatomic chains containing one Co atom as a magnetic impurity, and connected to two conducting leads with a fourfold symmetry axis. Using the information derived from ab initio calculations, we construct an effective model Ĥ(eff) that hybridizes a 3d(7) quadruplet at the Co site with two 3d(8) triplets through the hopping of 5d(xz) and 5d(yz) electrons of Au. The quadruplet is split by spin anisotropy due to spin-orbit coupling. Solving Ĥ(eff) with the numerical renormalization group we find that at low temperatures G(T)=a-b√[T] and the ground state impurity entropy is ln(2)/2, a behavior similar to the two-channel Kondo model. Stretching the chain leads to a non-Kondo phase, with the physics of the underscreened Kondo model at the quantum critical point.
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Affiliation(s)
- S Di Napoli
- Departamento de Física de la Materia Condensada, CAC-CNEA, Avenida General Paz 1499, 1650 San Martín, Provincia de Buenos Aires, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Buenos Aires C1033AAJ, Argentina
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11
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Chorley SJ, Galpin MR, Jayatilaka FW, Smith CG, Logan DE, Buitelaar MR. Tunable Kondo physics in a carbon nanotube double quantum dot. PHYSICAL REVIEW LETTERS 2012; 109:156804. [PMID: 23102352 DOI: 10.1103/physrevlett.109.156804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Indexed: 06/01/2023]
Abstract
We investigate a tunable two-impurity Kondo system in a strongly correlated carbon nanotube double quantum dot, accessing the full range of charge regimes. In the regime where both dots contain an unpaired electron, the system approaches the two-impurity Kondo model. At zero magnetic field the interdot coupling disrupts the Kondo physics and a local singlet state arises, but we are able to tune the crossover to a Kondo screened phase by application of a magnetic field. All results show good agreement with a numerical renormalization group study of the device.
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Affiliation(s)
- S J Chorley
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
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12
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Magnusson EB, Hasselmann N, Shelykh IA. Functional renormalization group approach to the singlet-triplet transition in quantum dots. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:365602. [PMID: 22906995 DOI: 10.1088/0953-8984/24/36/365602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a functional renormalization group approach to the zero bias transport properties of a quantum dot with two different orbitals and in the presence of Hund's coupling. Tuning the energy separation of the orbital states, the quantum dot can be driven through a singlet-triplet transition. Our approach, based on the approach by Karrasch et al (2006 Phys. Rev. B 73 235337), which we apply to spin-dependent interactions, recovers the key characteristics of the quantum dot transport properties with very little numerical effort. We present results on the conductance in the vicinity of the transition and compare our results both with previous numerical renormalization group results and with predictions of the perturbative renormalization group.
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Affiliation(s)
- E B Magnusson
- Science Institute, University of Iceland, Dunhagi 3, IS-107, Reykjavik, Iceland
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13
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Tosi L, Roura-Bas P, Aligia AA. Non-equilibrium conductance through a benzene molecule in the Kondo regime. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:365301. [PMID: 22892707 DOI: 10.1088/0953-8984/24/36/365301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Starting from exact eigenstates for a symmetric ring, we derive a low-energy effective generalized Anderson Hamiltonian which contains two spin doublets with opposite momenta and a singlet for the neutral molecule. For benzene, the singlet (doublets) represent the ground state of the neutral (singly charged) molecule. We calculate the non-equilibrium conductance through a benzene molecule, doped with one electron or a hole (i.e. in the Kondo regime), and connected to two conducting leads at different positions. We solve the problem using the Keldysh formalism and the non-crossing approximation. When the leads are connected in the para position (at 180°), the model is equivalent to the ordinary impurity Anderson model and its known properties are recovered. For other positions, there is a partial destructive interference in the co-tunneling processes involving the two doublets and, as a consequence, the Kondo temperature and the height and width of the central peak (for bias voltage V(b) near zero) of the differential conductance G = dI/dV(b) (where I is the current) are reduced. In addition, two peaks at finite V(b) appear. We study the position of these peaks, the temperature dependence of G and the spectral densities. Our formalism can also be applied to carbon nanotube quantum dots with intervalley mixing.
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Affiliation(s)
- L Tosi
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, 8400 Bariloche, Argentina
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14
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Aligia AA. Nonequilibrium conductance of a nanodevice for small bias voltage. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:015306. [PMID: 22156237 DOI: 10.1088/0953-8984/24/1/015306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Using nonequilibrium renormalized perturbation theory, we calculate the retarded and lesser self-energies, the spectral density ρ(ω) near the Fermi energy, and the conductance G through a quantum dot as a function of a small bias voltage V, in the general case of electron-hole asymmetry and intermediate valence. The linear terms in ω and V are given exactly in terms of thermodynamic quantities. When the energies necessary to add the first electron (Ed) and the second one (Ed + U) to the quantum dot are not symmetrically placed around the Fermi level, G has a term linear in V if, in addition, either the voltage drop or the coupling to the leads is not symmetric. The effects of temperature are discussed. The results simplify for a symmetric voltage drop, a situation usual in experiment.
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Affiliation(s)
- A A Aligia
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica,8400 Bariloche, Argentina
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