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Smith LW, Chen HB, Chang CW, Wu CW, Lo ST, Chao SH, Farrer I, Beere HE, Griffiths JP, Jones GAC, Ritchie DA, Chen YN, Chen TM. Electrically Controllable Kondo Correlation in Spin-Orbit-Coupled Quantum Point Contacts. PHYSICAL REVIEW LETTERS 2022; 128:027701. [PMID: 35089765 DOI: 10.1103/physrevlett.128.027701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Integrating the Kondo correlation and spin-orbit interactions, each of which have individually offered unprecedented means to manipulate electron spins, in a controllable way can open up new possibilities for spintronics. We demonstrate electrical control of the Kondo correlation by coupling the bound spin to leads with tunable Rashba spin-orbit interactions, realized in semiconductor quantum point contacts. We observe a transition from single to double peak zero-bias anomalies in nonequilibrium transport-the manifestation of the Kondo effect-indicating a controlled Kondo spin reversal using only spin-orbit interactions. Universal scaling of the Kondo conductance is demonstrated, implying that the spin-orbit interactions could enhance the Kondo temperature. A theoretical model based on quantum master equations is also developed to calculate the nonequilibrium quantum transport.
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Affiliation(s)
- Luke W Smith
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Hong-Bin Chen
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
| | - Che-Wei Chang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Chien-Wei Wu
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Shun-Tsung Lo
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Shih-Hsiang Chao
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - I Farrer
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
- Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom
| | - H E Beere
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - J P Griffiths
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - G A C Jones
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - D A Ritchie
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Yueh-Nan Chen
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
| | - Tse-Ming Chen
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
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2
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Hata T, Teratani Y, Arakawa T, Lee S, Ferrier M, Deblock R, Sakano R, Oguri A, Kobayashi K. Three-body correlations in nonlinear response of correlated quantum liquid. Nat Commun 2021; 12:3233. [PMID: 34050168 PMCID: PMC8163827 DOI: 10.1038/s41467-021-23467-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 04/26/2021] [Indexed: 11/09/2022] Open
Abstract
Behavior of quantum liquids is a fascinating topic in physics. Even in a strongly correlated case, the linear response of a given system to an external field is described by the fluctuation-dissipation relations based on the two-body correlations in the equilibrium. However, to explore nonlinear non-equilibrium behaviors of the system beyond this well-established regime, the role of higher order correlations starting from the three-body correlations must be revealed. In this work, we experimentally investigate a controllable quantum liquid realized in a Kondo-correlated quantum dot and prove the relevance of the three-body correlations in the nonlinear conductance at finite magnetic field, which validates the recent Fermi liquid theory extended to the non-equilibrium regime. Recent theory has shown that the non-equilibrium response of a Kondo model can be described by the Fermi liquid theory with three-body correlations. Here, the authors experimentally measure such correlations in the nonlinear conductance of a Kondo-correlated quantum dot.
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Affiliation(s)
- Tokuro Hata
- Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.
| | | | - Tomonori Arakawa
- Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.,Center for Spintronics Research Network, Osaka University, Toyonaka, Osaka, Japan
| | - Sanghyun Lee
- Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Meydi Ferrier
- Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.,Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, Orsay, France
| | - Richard Deblock
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, Orsay, France
| | - Rui Sakano
- The Institute for Solid State Physics, The University of Tokyo, Chiba, Japan
| | - Akira Oguri
- Department of Physics, Osaka City University, Osaka, Japan.,Nambu Yoichiro Institute of Theoretical and Experimental Physics, Osaka City University, Osaka, Japan
| | - Kensuke Kobayashi
- Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan. .,Institute for Physics of Intelligence and Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo, Japan. .,Trans-scale Quantum Science Institute, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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3
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Guo X, Zhu Q, Zhou L, Yu W, Lu W, Liang W. Evolution and universality of two-stage Kondo effect in single manganese phthalocyanine molecule transistors. Nat Commun 2021; 12:1566. [PMID: 33692347 PMCID: PMC7946881 DOI: 10.1038/s41467-021-21492-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 01/26/2021] [Indexed: 11/19/2022] Open
Abstract
The Kondo effect offers an important paradigm to understand strongly correlated many-body physics. Although under intensive study, some of the important properties of the Kondo effect, in systems where both itinerant coupling and localized coupling play significant roles, are still elusive. Here we report the evolution and universality of the two-stage Kondo effect, the simplest form where both couplings are important using single molecule transistor devices incorporating Manganese phthalocyanine molecules. The Kondo temperature T* of the two-stage Kondo effect evolves linearly against effective interaction of involved two spins. Observed Kondo resonance shows universal quadratic dependence with all adjustable parameters: temperature, magnetic field and biased voltages. The difference in nonequilibrium conductance of two-stage Kondo effect to spin 1/2 Kondo effect is also identified. Messages learned in this study fill in directive experimental evidence of the evolution of two-stage Kondo resonance near a quantum phase transition point, and help in understanding sophisticated molecular electron spectroscopy in a strong correlation regime. The Kondo effect can serve as a powerful paradigm to understand strongly correlated many-body processes in physics. Here, Guo et al. utilize single molecule transistor devices as a testbed to study multi-level Kondo correlation and show electrical gate evolution and the universality of the two-stage Kondo effect.
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Affiliation(s)
- Xiao Guo
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China.,Beijing National center for Condensed Matter Physics, Beijing Key Laboratory for Nanomaterials and Nanodevices, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China.,CAS Center of Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Qiuhao Zhu
- Beijing National center for Condensed Matter Physics, Beijing Key Laboratory for Nanomaterials and Nanodevices, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China.,CAS Center of Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Liyan Zhou
- Beijing National center for Condensed Matter Physics, Beijing Key Laboratory for Nanomaterials and Nanodevices, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China.,CAS Center of Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Wei Yu
- Beijing National center for Condensed Matter Physics, Beijing Key Laboratory for Nanomaterials and Nanodevices, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China.,CAS Center of Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Wengang Lu
- Beijing National center for Condensed Matter Physics, Beijing Key Laboratory for Nanomaterials and Nanodevices, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China.,CAS Center of Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Wenjie Liang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China. .,Beijing National center for Condensed Matter Physics, Beijing Key Laboratory for Nanomaterials and Nanodevices, Institute of Physics, Chinese Academy of Sciences, Beijing, P.R. China. .,CAS Center of Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, P.R. China.
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4
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Teratani Y, Sakano R, Oguri A. Fermi Liquid Theory for Nonlinear Transport through a Multilevel Anderson Impurity. PHYSICAL REVIEW LETTERS 2020; 125:216801. [PMID: 33274972 DOI: 10.1103/physrevlett.125.216801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 10/15/2020] [Indexed: 06/12/2023]
Abstract
We present a microscopic Fermi liquid view on the low-energy transport through an Anderson impurity with N discrete levels, at arbitrary electron filling N_{d}. It is applied to nonequilibrium current fluctuations, for which the two-quasiparticle collision integral and the three-body correlations that determine the quasiparticle energy shift play important roles. Using the numerical renormalization group up to N=6, we find that for strong interactions the three-body fluctuations are determined by a single parameter other than the Kondo energy scale in a wide filling range 1≲N_{d}≲N-1. It significantly affects the current noise for N>2 and the behavior of noise in magnetic fields.
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Affiliation(s)
- Yoshimichi Teratani
- Department of Physics, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Rui Sakano
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Akira Oguri
- Department of Physics, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan and Nambu Yoichiro Institute of Theoretical and Experimental Physics, Osaka City University, Osaka 558-8585, Japan
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5
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Zhang HD, Cui L, Gong H, Xu RX, Zheng X, Yan Y. Hierarchical equations of motion method based on Fano spectrum decomposition for low temperature environments. J Chem Phys 2020; 152:064107. [PMID: 32061227 DOI: 10.1063/1.5136093] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The hierarchical equations of motion (HEOM) method has become one of the most popular methods for the studies of the open quantum system. However, its applicability to systems at ultra-low temperatures is largely restrained by the enormous computational cost, which is caused by the numerous exponential functions required to accurately characterize the non-Markovian memory of the reservoir environment. To overcome this problem, a Fano spectrum decomposition (FSD) scheme has been proposed recently [Cui et al., J. Chem. Phys. 151, 024110 (2019)], which expands the reservoir correlation functions using polynomial-exponential functions and hence greatly reduces the size of the memory basis set. In this work, we explicitly establish the FSD-based HEOM formalisms for both bosonic and fermionic environments. The accuracy and efficiency of the FSD-based HEOM are exemplified by the calculated low-temperature dissipative dynamics of a spin-boson model and the dynamic and static properties of a single-orbital Anderson impurity model in the Kondo regime. The encouraging numerical results highlight the practicality and usefulness of the FSD-based HEOM method for general open systems at ultra-low temperatures.
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Affiliation(s)
- Hou-Dao Zhang
- 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
| | - Lei Cui
- 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
| | - Hong Gong
- 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
| | - Rui-Xue Xu
- 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
| | - Xiao Zheng
- 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
| | - YiJing Yan
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, China
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6
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Schiro M, Scarlatella O. Quantum impurity models coupled to Markovian and non-Markovian baths. J Chem Phys 2019; 151:044102. [PMID: 31370519 DOI: 10.1063/1.5100157] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We develop a method to study quantum impurity models, small interacting quantum systems bilinearly coupled to an environment, in the presence of an additional Markovian quantum bath, with a generic nonlinear coupling to the impurity. We aim at computing the evolution operator of the reduced density matrix of the impurity, obtained after tracing out all the environmental degrees of freedom. First, we derive an exact real-time hybridization expansion for this quantity, which generalizes the result obtained in the absence of the additional Markovian dissipation and which could be amenable to stochastic sampling through diagrammatic Monte Carlo. Then, we obtain a Dyson equation for this quantity and we evaluate its self-energy with a resummation technique known as the noncrossing approximation. We apply this novel approach to a simple fermionic impurity coupled to a zero temperature fermionic bath and in the presence of Markovian pump, losses, and dephasing.
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Affiliation(s)
- Marco Schiro
- JEIP, USR 3573 CNRS, Collége de France, PSL Research University, 11, place Marcelin Berthelot, 7 5231 Paris Cedex 05, France
| | - Orazio Scarlatella
- Institut de Physique Théorique, Université Paris Saclay, CNRS, CEA, F-91191 Gif-sur-Yvette, France
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7
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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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8
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Bayat A, Alkurtass B, Sodano P, Johannesson H, Bose S. Measurement Quench in Many-Body Systems. PHYSICAL REVIEW LETTERS 2018; 121:030601. [PMID: 30085809 DOI: 10.1103/physrevlett.121.030601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 05/09/2018] [Indexed: 06/08/2023]
Abstract
Measurement is one of the key concepts which discriminates classical and quantum physics. Unlike classical systems, a measurement on a quantum system typically alters it drastically as a result of wave function collapse. Here we suggest that this feature can be exploited for inducing quench dynamics in a many-body system while leaving its Hamiltonian unchanged. Importantly, by doing away with dedicated macroscopic devices for inducing a quench-using instead the indispensable measurement apparatus only-the protocol is expected to be easier to implement and more resilient against decoherence. By way of various case studies, we show that our scheme also has decisive advantages beyond reducing decoherence-for spectroscopy purposes and probing nonequilibrium scaling of critical and quantum impurity many-body systems.
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Affiliation(s)
- Abolfazl Bayat
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610051, China
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - Bedoor Alkurtass
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
- Department of Physics and Astronomy, King Saud University, Riyadh 11451, Saudi Arabia
| | - Pasquale Sodano
- International Institute of Physics, Universidade Federal do Rio Grande do Norte, 59078-400 Natal-RN, Brazil
| | - Henrik Johannesson
- Department of Physics, University of Gothenburg, SE 412 96 Gothenburg, Sweden
- Beijing Computational Science Research Center, Beijing 100094, China
| | - Sougato Bose
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
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9
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Aligia AA. Leading temperature dependence of the conductance in Kondo-correlated quantum dots. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:155304. [PMID: 29508772 DOI: 10.1088/1361-648x/aab45b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Using renormalized perturbation theory in the Coulomb repulsion, we derive an analytical expression for the leading term in the temperature dependence of the conductance through a quantum dot described by the impurity Anderson model, in terms of the renormalized parameters of the model. Taking these parameters from the literature, we compare the results with published ones calculated using the numerical renormalization group obtaining a very good agreement. The approach is superior to alternative perturbative treatments. We compare in particular to the results of a simple interpolative perturbation approach.
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Affiliation(s)
- A A Aligia
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, CONICET, 8400 Bariloche, Argentina
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10
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Oguri A, Hewson AC. Higher-Order Fermi-Liquid Corrections for an Anderson Impurity Away from Half Filling. PHYSICAL REVIEW LETTERS 2018; 120:126802. [PMID: 29694075 DOI: 10.1103/physrevlett.120.126802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/20/2017] [Indexed: 06/08/2023]
Abstract
We study the higher-order Fermi-liquid relations of Kondo systems for arbitrary impurity-electron fillings, extending the many-body quantum theoretical approach of Yamada and Yosida. It includes, partly, a microscopic clarification of the related achievements based on Nozières' phenomenological description: Filippone, Moca, von Delft, and Mora [Phys. Rev. B 95, 165404 (2017)PRBMDO2469-995010.1103/PhysRevB.95.165404]. In our formulation, the Fermi-liquid parameters such as the quasiparticle energy, damping, and transport coefficients are related to each other through the total vertex Γ_{σσ^{'};σ^{'}σ}(ω,ω^{'};ω^{'},ω), which may be regarded as a generalized Landau quasiparticle interaction. We obtain exactly this function up to linear order with respect to the frequencies ω and ω^{'} using the antisymmetry and analytic properties. The coefficients acquire additional contributions of three-body fluctuations away from half filling through the nonlinear susceptibilities. We also apply the formulation to nonequilibrium transport through a quantum dot, and clarify how the zero-bias peak evolves in a magnetic field.
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Affiliation(s)
- Akira Oguri
- Department of Physics, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - A C Hewson
- Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom
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11
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Li Z, Wei J, Zheng X, Yan Y, Luo HG. Corrected Kondo temperature beyond the conventional Kondo scaling limit. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:175601. [PMID: 28218894 DOI: 10.1088/1361-648x/aa6183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In the Kondo systems such as the magnetic impurity screened by the conduction electrons in a metal host, as well as the quantum dots connected by the leads, the low energy behaviors have universal dependence on the [Formula: see text] or [Formula: see text], where [Formula: see text] is the conventional Kondo temperature. However, it was shown that this scaling behavior is only valid at low-energy; this is called the Kondo scaling limit. Here we explore the extention of the scaling parameter range by introducing the corrected Kondo temperature T K, which may depend on the temperature and bias, as well as the other external parameters. We define the corrected Kondo temperature by scaling the local density of states near the Fermi level, obtained by accurate hierarchy of equations of motion approach at finite temperature and finite bias, and thus obtain a phenomenological expression of the corrected Kondo temperature. By using the corrected Kondo temperature as a characteristic energy scale, the conductance of the quantum dot can be well scaled in a wide parameter range, even two orders beyond the conventional scaling parameter range. Our work indicates that the Kondo scaling, although dominated by the conventional Kondo temperature in the low-energy of the Kondo system, could be extended to a higher energy regime, which is useful for analyzing the physics of the Kondo transport in non-equilibrium or high temperature cases.
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Affiliation(s)
- ZhenHua Li
- Beijing Computational Science Research Center, Beijing 100193, People's Republic of China. Department of Physics, Renmin University of China, Beijing 100872, People's Republic of China
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12
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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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13
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Ye L, Wang X, Hou D, Xu RX, Zheng X, Yan Y. HEOM-QUICK: a program for accurate, efficient, and universal characterization of strongly correlated quantum impurity systems. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2016. [DOI: 10.1002/wcms.1269] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- LvZhou Ye
- 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 China
| | - Xiaoli Wang
- 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 China
| | - Dong Hou
- 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 China
| | - Rui-Xue Xu
- 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 China
| | - Xiao Zheng
- 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 China
| | - YiJing Yan
- Hefei National Laboratory for Physical Sciences at the Microscale and iChEM (Collaborative Innovation Center of Chemistry for Energy Materials); University of Science and Technology of China; Hefei China
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14
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Wang Y, Zheng X, Li B, Yang J. Understanding the Kondo resonance in the d-CoPc/Au(111) adsorption system. J Chem Phys 2014; 141:084713. [DOI: 10.1063/1.4893953] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Büsser CA, Heidrich-Meisner F. Inducing spin correlations and entanglement in a double quantum dot through nonequilibrium transport. PHYSICAL REVIEW LETTERS 2013; 111:246807. [PMID: 24483691 DOI: 10.1103/physrevlett.111.246807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Indexed: 06/03/2023]
Abstract
For a double quantum dot system in a parallel geometry, we demonstrate that by combining the effects of a flux and driving an electrical current through the structure, the spin correlations between electrons localized in the dots can be controlled at will. In particular, a current can induce spin correlations even if the spins are uncorrelated in the initial equilibrium state. Therefore, we are able to engineer an entangled state in this double-dot structure. We take many-body correlations fully into account by simulating the real-time dynamics using the time-dependent density matrix renormalization group method. Using a canonical transformation, we provide an intuitive explanation for our results, related to Ruderman-Kittel-Kasuya-Yoshida physics driven by the bias.
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Affiliation(s)
- C A Büsser
- Department of Physics and Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-University Munich, 80333 Munich, Germany
| | - F Heidrich-Meisner
- Department of Physics and Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-University Munich, 80333 Munich, Germany and Institute for Theoretical Physics II, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
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16
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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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17
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Muñoz E, Bolech CJ, Kirchner S. Universal out-of-equilibrium transport in Kondo-correlated quantum dots: renormalized dual fermions on the Keldysh contour. PHYSICAL REVIEW LETTERS 2013; 110:016601. [PMID: 23383817 DOI: 10.1103/physrevlett.110.016601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 11/02/2012] [Indexed: 06/01/2023]
Abstract
The nonlinear conductance of semiconductor heterostructures and single molecule devices exhibiting Kondo physics has recently attracted attention. We address the observed sample dependence of the measured steady state transport coefficients by considering additional electronic contributions in the effective low-energy model underlying these experiments that are absent in particle-hole symmetric setups. A novel version of the superperturbation theory of Hafermann et al. in terms of dual fermions is developed, which correctly captures the low-temperature behavior. We compare our results with the measured transport coefficients.
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Affiliation(s)
- Enrique Muñoz
- Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
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18
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Sakano R, Nishikawa Y, Oguri A, Hewson AC, Tarucha S. Full counting statistics for orbital-degenerate impurity Anderson model with Hund's rule exchange coupling. PHYSICAL REVIEW LETTERS 2012; 108:266401. [PMID: 23004997 DOI: 10.1103/physrevlett.108.266401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Indexed: 06/01/2023]
Abstract
We study nonequilibrium current fluctuations through a quantum dot, which includes a ferromagnetic Hund's rule coupling J, in the low-energy Fermi liquid regime using the renormalized perturbation theory. The resulting cumulant for the current distribution in the particle-hole symmetric case shows that spin-triplet and spin-singlet pairs of quasiparticles are formed in the current due to the Hund's rule coupling, and these pairs enhance the current fluctuations. In the fully screened higher-spin Kondo limit, the Fano factor takes a value F(b)=(9M+6)/(5M+4) determined by the orbital degeneracy M. We also investigate the crossover between the small and large J limits in the two-orbital case M=2, using the numerical renormalization group approach.
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Affiliation(s)
- Rui Sakano
- Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo, Japan
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19
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Aron C, Kotliar G, Weber C. Dimensional crossover driven by an electric field. PHYSICAL REVIEW LETTERS 2012; 108:086401. [PMID: 22463546 DOI: 10.1103/physrevlett.108.086401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Indexed: 05/31/2023]
Abstract
We study the steady-state dynamics of the Hubbard model driven out of equilibrium by a constant electric field and coupled to a dissipative heat bath. For a very strong field, we find a dimensional reduction: the system behaves as an equilibrium Hubbard model in lower dimensions. We derive steady-state equations for the dynamical mean-field theory in the presence of dissipation. We discuss how the electric field induced dimensional crossover affects the momentum resolved and integrated spectral functions, the energy distribution function, as well as the steady current in the nonlinear regime.
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Affiliation(s)
- Camille Aron
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
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20
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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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21
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Delbecq MR, Schmitt V, Parmentier FD, Roch N, Viennot JJ, Fève G, Huard B, Mora C, Cottet A, Kontos T. Coupling a quantum dot, fermionic leads, and a microwave cavity on a chip. PHYSICAL REVIEW LETTERS 2011; 107:256804. [PMID: 22243102 DOI: 10.1103/physrevlett.107.256804] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Indexed: 05/23/2023]
Abstract
We demonstrate a hybrid architecture consisting of a quantum dot circuit coupled to a single mode of the electromagnetic field. We use single wall carbon nanotube based circuits inserted in superconducting microwave cavities. By probing the nanotube dot using a dispersive readout in the Coulomb blockade and the Kondo regime, we determine an electron-photon coupling strength which should enable circuit QED experiments with more complex quantum dot circuits.
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Affiliation(s)
- M R Delbecq
- Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS UMR 8551, Laboratoire associé aux universités Pierre et Marie Curie et Denis Diderot, 24, rue Lhomond, 75231 Paris Cedex 05, France
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22
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Mierzejewski M, Vidmar L, Bonča J, Prelovšek P. Nonequilibrium quantum dynamics of a charge carrier doped into a Mott insulator. PHYSICAL REVIEW LETTERS 2011; 106:196401. [PMID: 21668177 DOI: 10.1103/physrevlett.106.196401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Indexed: 05/30/2023]
Abstract
We study real-time dynamics of a charge carrier introduced into an undoped Mott insulator propagating under a constant electric field F on the t-J ladder and a square lattice. We calculate the quasistationary current. In both systems an adiabatic regime is observed followed by a positive differential resistivity (PDR) at moderate fields where the carrier mobility is determined. Quantitative differences between the ladder and two-dimensional (2D) systems emerge when at large fields both systems enter the negative differential resistivity (NDR) regime. In the ladder system Bloch-like oscillations prevail, while in two dimensions the current remains finite, proportional to 1/F. The crossover between the PDR and NDR in two dimensions is accompanied by a change of the spatial structure of the propagating spin polaron.
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Affiliation(s)
- M Mierzejewski
- Institute of Physics, University of Silesia, 40-007 Katowice, Poland
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23
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Yamauchi Y, Sekiguchi K, Chida K, Arakawa T, Nakamura S, Kobayashi K, Ono T, Fujii T, Sakano R. Evolution of the Kondo effect in a quantum dot probed by shot noise. PHYSICAL REVIEW LETTERS 2011; 106:176601. [PMID: 21635054 DOI: 10.1103/physrevlett.106.176601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Indexed: 05/30/2023]
Abstract
We measure the current and shot noise in a quantum dot in the Kondo regime to address the nonequilibrium properties of the Kondo effect. By systematically tuning the temperature and gate voltages to define the level positions in the quantum dot, we observe an enhancement of the shot noise as temperature decreases below the Kondo temperature, which indicates that the two-particle scattering process grows as the Kondo state evolves. Below the Kondo temperature, the Fano factor defined at finite temperature is found to exceed the expected value of unity from the noninteracting model, reaching 1.8±0.2.
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Affiliation(s)
- Yoshiaki Yamauchi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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24
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Balseiro CA, Usaj G, Sánchez MJ. Out of equilibrium transport through an Anderson impurity: probing scaling laws within the equation of motion approach. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:425602. [PMID: 21403312 DOI: 10.1088/0953-8984/22/42/425602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We study non-equilibrium electron transport through a quantum impurity coupled to metallic leads using the equation of motion technique at finite temperature T. Assuming that the interactions are taking place solely in the impurity and focusing on the infinite Hubbard limit, we compute the out of equilibrium density of states and the differential conductance G(2)(T, V) in order to test several scaling laws. We find that G(2)(T, V)/G(2)(T, 0) is a universal function of both eV/T(K) and T/T(K), T(K) being the Kondo temperature. The effect of an in-plane magnetic field on the splitting of the zero bias anomaly in the differential conductance is also analyzed. For a Zeeman splitting Δ, the computed differential conductance peak splitting depends only on Δ/T(K), and for large fields approaches the value of 2Δ. Besides studying the traditional two leads setup, we also consider other configurations that mimic recent experiments, namely, an impurity embedded in a mesoscopic wire and the presence of a third weakly coupled lead. In these cases, a double peak structure of the Kondo resonance is clearly obtained in the differential conductance while the amplitude of the highest peak is shown to decrease as ln(eV/T(K)). Several features of these results are in qualitative agreement with recent experimental observations reported on quantum dots.
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Affiliation(s)
- C A Balseiro
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, 8400 S C de Bariloche, Argentina
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25
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Abstract
Molecular electronic devices currently serve as a platform for studying a variety of physical phenomena only accessible at the nanometer scale. One such phenomenon is the highly correlated electronic state responsible for the Kondo effect, manifested here as a "Kondo resonance" in the conductance. Because the Kondo effect results from strong electron-electron interactions, it is not captured by the usual quantum chemistry approaches traditionally applied to understand chemical electron transfer. In this review, we will discuss the origins and phenomenology of Kondo resonances observed in single-molecule devices, focusing primarily on the spin-1/2 Kondo state arising from a single unpaired electron. We explore the rich physical system of a single-molecule device, which offers a unique spectroscopic tool for investigating the interplay of emergent Kondo behavior and such properties as molecular orbital transitions and vibrational modes. We will additionally address more exotic systems, such as higher spin states in the Kondo regime, and we will review recent experimental advances in the ability to manipulate and exert control over these nanoscale devices.
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Affiliation(s)
- Gavin David Scott
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA.
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26
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Roch N, Florens S, Costi TA, Wernsdorfer W, Balestro F. Observation of the underscreened Kondo effect in a molecular transistor. PHYSICAL REVIEW LETTERS 2009; 103:197202. [PMID: 20365950 DOI: 10.1103/physrevlett.103.197202] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Indexed: 05/29/2023]
Abstract
We present the first quantitative experimental evidence for the underscreened Kondo effect, an incomplete compensation of a quantized magnetic moment by conduction electrons, as originally proposed by Nozières and Blandin. The device consists of an even charge spin S=1 molecular quantum dot, obtained by electromigration of C60 molecules into gold nanogaps and operated in a dilution fridge. The persistence of logarithmic singularities in the low temperature conductance is demonstrated by a comparison to the fully screened configuration obtained in odd charge spin S=1/2 Coulomb diamonds. We also discover an extreme sensitivity of the underscreened Kondo resonance to the magnetic field that we confirm on the basis of numerical renormalization group calculations.
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Affiliation(s)
- Nicolas Roch
- Institut Néel, associé à l'UJF, CNRS, BP 166, 38042 Grenoble Cedex 9, France
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27
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León Hilario LM, Aligia AA. Photoluminescence of a quantum dot hybridized with a continuum of extended states. PHYSICAL REVIEW LETTERS 2009; 103:156802. [PMID: 19905656 DOI: 10.1103/physrevlett.103.156802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Indexed: 05/28/2023]
Abstract
We calculate the intensity of photon emission from a trion in a single quantum dot, as a function of energy and gate voltage, using the impurity Anderson model and variational wave functions. Assuming a flat density of conduction states and constant hybridization energy, the results agree with the main features observed in recent experiments: nonmonotonic dependence of the energy on gate voltage, non-Lorentzian line shapes, and a linewidth that increases near the regions of instability of the single electron final state to occupations zero or two.
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Affiliation(s)
- L M León Hilario
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, 8400 Bariloche, Argentina
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28
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Sela E, Affleck I. Resonant pair tunneling in double quantum dots. PHYSICAL REVIEW LETTERS 2009; 103:087204. [PMID: 19792756 DOI: 10.1103/physrevlett.103.087204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Indexed: 05/28/2023]
Abstract
We present exact results on the nonequilibrium current fluctuations for 2 quantum dots in series throughout a crossover from non-Fermi liquid to Fermi liquid behavior described by the 2 impurity Kondo model. The result corresponds to resonant tunneling of carriers of charge 2e for a critical interimpurity coupling. At low energy scales, the result can be understood from a Fermi liquid approach that we develop and use to also study nonequilibrium transport in an alternative double dot realization of the 2 impurity Kondo model under current experimental study.
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Affiliation(s)
- Eran Sela
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z1
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29
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Liu TM, Hemingway B, Kogan A, Herbert S, Melloch M. Magnetic-field-induced crossover to a nonuniversal regime in a Kondo dot. PHYSICAL REVIEW LETTERS 2009; 103:026803. [PMID: 19659231 DOI: 10.1103/physrevlett.103.026803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Indexed: 05/28/2023]
Abstract
We have measured the magnetic splitting Delta K of a Kondo peak in the differential conductance of a single-electron transistor while tuning the Kondo temperature T K along two different paths in parameter space: varying the dot-lead coupling at a constant dot energy and vice versa. At a high magnetic field B, the changes of DeltaK with TK along the two paths have opposite signs, indicating that Delta K is not a universal function of TK. At low B, we observe a decrease in DeltaK with TK along both paths, in agreement with theoretical predictions. Furthermore, we find Delta K/Delta<1 at low B and Delta K/Delta>1 at high B, where Delta is the Zeeman energy of the bare spin, in the same system.
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Affiliation(s)
- Tai-Min Liu
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, USA
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30
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Sela E, Affleck I. Nonequilibrium transport through double quantum dots: exact results near a quantum critical point. PHYSICAL REVIEW LETTERS 2009; 102:047201. [PMID: 19257469 DOI: 10.1103/physrevlett.102.047201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Indexed: 05/27/2023]
Abstract
While violations of the Fermi liquid paradigm for metals are of great interest in various physical systems, quantum impurity models are among the few cases where exact theoretical results are available. Double quantum dots can provide an experimental realization of the 2 impurity Kondo model which exhibits a non-Fermi-liquid quantum critical point at a special value of its parameters. We present an exact universal result for the finite temperature nonlinear conductance along the crossover from this quantum critical point to the low energy Fermi liquid phase.
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Affiliation(s)
- Eran Sela
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z1
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31
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Altland A, Egger R. Nonequilibrium dephasing in Coulomb blockaded quantum dots. PHYSICAL REVIEW LETTERS 2009; 102:026805. [PMID: 19257305 DOI: 10.1103/physrevlett.102.026805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Indexed: 05/27/2023]
Abstract
We present a theory of zero-bias anomalies and dephasing rates for a Coulomb-blockaded quantum dot, driven out of equilibrium by coupling to voltage biased source and drain leads. We interpret our results in terms of the statistics of voltage fluctuations in the system.
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Affiliation(s)
- Alexander Altland
- Institut für Theoretische Physik, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany
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32
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Buizert C, Koppens FHL, Pioro-Ladrière M, Tranitz HP, Vink IT, Tarucha S, Wegscheider W, Vandersypen LMK. Insitu reduction of charge noise in GaAs/AlxGa1-xAs Schottky-gated devices. PHYSICAL REVIEW LETTERS 2008; 101:226603. [PMID: 19113501 DOI: 10.1103/physrevlett.101.226603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Indexed: 05/27/2023]
Abstract
We show that an insulated electrostatic gate can be used to strongly suppress ubiquitous background charge noise in Schottky-gated GaAs/AlGaAs devices. Via a 2D self-consistent simulation of the conduction band profile we show that this observation can be explained by reduced leakage of electrons from the Schottky gates into the semiconductor through the Schottky barrier, consistent with the effect of "bias cooling." Upon noise reduction, the noise power spectrum generally changes from Lorentzian to 1/f type. By comparing wafers with different Al content, we exclude that DX centers play a dominant role in the charge noise.
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Affiliation(s)
- Christo Buizert
- Kavli Institute of NanoScience, Delft University of Technology, PO Box 5046, 2600 GA, The Netherlands
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