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Wang X, Zhu X, Wu P, Li Q, Li Z, Zhang X, Liu Z, Zhang Y, Du P. Differences in Kondo Splitting of Surface Quantum Systems Induced by Two Distinct Magnetic Tips: A Joint Method of DFT and HEOM. J Phys Chem A 2024; 128:4750-4760. [PMID: 38832647 DOI: 10.1021/acs.jpca.4c02067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The interactions between a magnetic tip and local spin impurities initiate unconventional Kondo phenomena, such as asymmetric suppression or even splitting of the Kondo peak. However, a lack of realistic theoretical models and comprehensive explanations for this phenomenon persists due to the complexity of the interactions. This research employs a joint method of density functional theory (DFT) and hierarchical equation of motion (HEOM) to simulate and contrast the modulation of the spin state and Kondo behavior in the Fe/Cu(100) system with two distinct magnetic tips. A cobalt tip, possessing a larger magnetic moment, incites greater atomic displacement of the iron atom, more notable alterations in electronic structure, and enhanced charge transfer with the environment compared with the control process utilizing a nickel tip. Furthermore, the Kondo resonance undergoes asymmetric splitting as a result of the ferromagnetic correlation between the iron atom and the magnetic tip. The Co tip's higher spin polarization results in a wider spacing between the splitting peaks. This investigation underscores the precision of the DFT + HEOM approach in predicting complex quantum phenomena and explaining the underlying physical principles. This provides valuable theoretical support for developing more sophisticated quantum regulation experiments.
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Affiliation(s)
- Xiaoli Wang
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Xinru Zhu
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Ping Wu
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Qing Li
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Zhen Li
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Xiaolei Zhang
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Zhongmin Liu
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Yuexing Zhang
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Pengli Du
- College of Chemical Engineering, Qinghai University, Xining 810016, PR China
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2
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Wang L, Bai D, Xia Y, Ho W. Electrical Manipulation of Quantum Coherence in a Two-Level Molecular System. PHYSICAL REVIEW LETTERS 2023; 130:096201. [PMID: 36930940 DOI: 10.1103/physrevlett.130.096201] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
We report the manipulation of ultrafast quantum coherence of a two-level single hydrogen molecular system by employing static electric field from the sample bias in a femtosecond terahertz scanning tunneling microscope. A H_{2} molecule adsorbed on the polar Cu_{2}N surface develops an electric dipole and exhibits a giant Stark effect. An avoided crossing of the quantum state energy levels is derived from the resonant frequency of the single H_{2} two levels in a double-well potential. The dephasing time of the initial wave packet can also be changed by applying the electric field. The electrical manipulation for different tunneling gaps in three dimensions allows quantification of the surface electrostatic fields at the atomic scale. Our work demonstrated the potential application of molecules as controllable two-level molecular systems.
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Affiliation(s)
- Likun Wang
- Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-4575, USA
| | - Dan Bai
- Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-4575, USA
| | - Yunpeng Xia
- Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-4575, USA
| | - W Ho
- Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697-4575, USA
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, USA
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3
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Wang X, Zhuang Q, Wu P, Liu L, Wang F, Zhang X, Li X, Zheng X. Tweezer-like magnetic tip control of the local spin state in the FeOEP/Pb(111) adsorption system: a preliminary exploration based on first-principles calculations. NANOSCALE 2023; 15:2369-2376. [PMID: 36648279 DOI: 10.1039/d2nr04379c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The magnetic interactions between the spin-polarized scanning tunnelling microscopy (SP-STM) tip and the localized spin impurities lead to various forms of the Kondo effect. Although these intriguing phenomena enrich Kondo physics, detailed theoretical simulations and explanations are still lacking due to the rather complex formation mechanisms. Here, by combining density functional theory (DFT), complete active space self-consistent field (CASSCF) theory, and hierarchical equations of motion (HEOM) methods, we perform first-principles-based simulation to elaborate the regulation process of the magnetic Co-tip on the spin state and transport behaviour of FeOEP/Pb(111) system. Compared with the non-magnetic tip, the stronger interaction between the magnetic tip and FeOEP molecule results in a more drastic deformation of the molecular structure with more electron transfer from the local environment to Fe-3d orbitals. The magnetic anisotropy of FeOEP changes very drastically from positive values in the tunnelling region to negative values in the contact region. The ferromagnetic electron correlation between the magnetic tip and the molecule induces an asymmetric Kondo line-shape near the Fermi level. This work highlights that the DFT + CASSCF + HEOM approach can not only predict complex quantum phenomena and explain underlying physical mechanisms, but also facilitate the design of more fascinating quantum control experiments.
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Affiliation(s)
- Xiaoli Wang
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Qingfeng Zhuang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Ping Wu
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Leifang Liu
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Fang Wang
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Xiaolei Zhang
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Xiangyang Li
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Xiao Zheng
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
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4
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Ramachandran A, Wilbur GR, O'Neal S, Deppe DG, Hall KC. Suppression of decoherence tied to electron-phonon coupling in telecom-compatible quantum dots: low-threshold reappearance regime for quantum state inversion. OPTICS LETTERS 2020; 45:6498-6501. [PMID: 33258845 DOI: 10.1364/ol.403590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/01/2020] [Indexed: 06/12/2023]
Abstract
We demonstrate suppression of dephasing tied to deformation potential coupling of confined electrons to longitudinal acoustic (LA) phonons in optical control experiments on large semiconductor quantum dots (QDs) with emission compatible with the low-dispersion telecommunications band at 1.3 µm. By exploiting the sensitivity of the electron-phonon spectral density to the size and shape of the QD, we demonstrate a fourfold reduction in the threshold pulse area required to enter the decoupled regime for exciton inversion using adiabatic rapid passage (ARP). Our calculations of the quantum state dynamics indicate that the symmetry of the QD wave function provides an additional means to engineer the electron-phonon interaction. Our findings will support the development of solid-state quantum emitters in future distributed quantum networks using semiconductor QDs.
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Complete Coherent Control of a Quantum Dot Strongly Coupled to a Nanocavity. Sci Rep 2016; 6:25172. [PMID: 27112420 PMCID: PMC4845032 DOI: 10.1038/srep25172] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 04/12/2016] [Indexed: 11/08/2022] Open
Abstract
Strongly coupled quantum dot-cavity systems provide a non-linear configuration of hybridized light-matter states with promising quantum-optical applications. Here, we investigate the coherent interaction between strong laser pulses and quantum dot-cavity polaritons. Resonant excitation of polaritonic states and their interaction with phonons allow us to observe coherent Rabi oscillations and Ramsey fringes. Furthermore, we demonstrate complete coherent control of a quantum dot-photonic crystal cavity based quantum-bit. By controlling the excitation power and phase in a two-pulse excitation scheme we achieve access to the full Bloch sphere. Quantum-optical simulations are in good agreement with our experiments and provide insight into the decoherence mechanisms.
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Gamouras A, Mathew R, Freisem S, Deppe DG, Hall KC. Simultaneous deterministic control of distant qubits in two semiconductor quantum dots. NANO LETTERS 2013; 13:4666-4670. [PMID: 24001027 DOI: 10.1021/nl4018176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In optimal quantum control (OQC), a target quantum state of matter is achieved by tailoring the phase and amplitude of the control Hamiltonian through femtosecond pulse-shaping techniques and powerful adaptive feedback algorithms. Motivated by recent applications of OQC in quantum information science as an approach to optimizing quantum gates in atomic and molecular systems, here we report the experimental implementation of OQC in a solid-state system consisting of distinguishable semiconductor quantum dots. We demonstrate simultaneous high-fidelity π and 2π single qubit gates in two different quantum dots using a single engineered infrared femtosecond pulse. These experiments enhance the scalability of semiconductor-based quantum hardware and lay the foundation for applications of pulse shaping to optimize quantum gates in other solid-state systems.
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Affiliation(s)
- A Gamouras
- Department of Physics and Atmospheric Science, Dalhousie University , Halifax, Nova Scotia B3H4R2, Canada
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Wei HR, Deng FG. Scalable photonic quantum computing assisted by quantum-dot spin in double-sided optical microcavity. OPTICS EXPRESS 2013; 21:17671-17685. [PMID: 23938640 DOI: 10.1364/oe.21.017671] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We investigate the possibility of achieving scalable photonic quantum computing by the giant optical circular birefringence induced by a quantum-dot spin in a double-sided optical microcavity as a result of cavity quantum electrodynamics. We construct a deterministic controlled-not gate on two photonic qubits by two single-photon input-output processes and the readout on an electron-medium spin confined in an optical resonant microcavity. This idea could be applied to multi-qubit gates on photonic qubits and we give the quantum circuit for a three-photon Toffoli gate. High fidelities and high efficiencies could be achieved when the side leakage to the cavity loss rate is low. It is worth pointing out that our devices work in both the strong and the weak coupling regimes.
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Affiliation(s)
- Hai-Rui Wei
- Department of Physics, Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
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Ladd TD, Press D, De Greve K, McMahon PL, Friess B, Schneider C, Kamp M, Höfling S, Forchel A, Yamamoto Y. Pulsed nuclear pumping and spin diffusion in a single charged quantum dot. PHYSICAL REVIEW LETTERS 2010; 105:107401. [PMID: 20867546 DOI: 10.1103/physrevlett.105.107401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Indexed: 05/29/2023]
Abstract
We report the observation of a feedback process between the nuclear spins in a single charged quantum dot under coherently pulsed optical excitation and its trion transition. The optical pulse sequence intersperses resonant narrow-band pumping for spin initialization with off-resonant ultrafast pulses for coherent electron-spin rotation. A hysteretic sawtooth pattern in the free-induction decay of the single electron spin is observed; a mathematical model indicates a competition between optical nuclear pumping and nuclear spin-diffusion. This effect allows dynamic tuning of the electron Larmor frequency to a value determined by the pulse timing, potentially allowing more complex coherent control operations.
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Affiliation(s)
- Thaddeus D Ladd
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.
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Claassen M, Türeci HE, Imamoğlu A. Solid-state spin-photon quantum interface without spin-orbit coupling. PHYSICAL REVIEW LETTERS 2010; 104:177403. [PMID: 20482141 DOI: 10.1103/physrevlett.104.177403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Indexed: 05/29/2023]
Abstract
We show that coherent optical manipulation of a single confined spin is possible even in the absence of spin-orbit coupling. To this end, we consider the non-Markovian dynamics of a single valence orbital hole spin that has optically induced spin-exchange coupling to a low-temperature partially polarized electron gas. We show that the fermionic nature of the reservoir induces a coherent component to the hole spin dynamics that does not generate entanglement with the reservoir modes. We analyze in detail the competition of this reservoir-assisted coherent contribution with dissipative components displaying markedly different behavior at different time scales and determine the fidelity of optically controlled spin rotations.
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Affiliation(s)
- Martin Claassen
- Institute for Quantum Electronics, ETH-Zürich, CH-8093 Zürich, Switzerland
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10
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Kim ED, Truex K, Xu X, Sun B, Steel DG, Bracker AS, Gammon D, Sham LJ. Fast spin rotations by optically controlled geometric phases in a charge-tunable InAs quantum dot. PHYSICAL REVIEW LETTERS 2010; 104:167401. [PMID: 20482081 DOI: 10.1103/physrevlett.104.167401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Indexed: 05/29/2023]
Abstract
We demonstrate optical control of the geometric phase acquired by one of the spin states of an electron confined in a charge-tunable InAs quantum dot via cyclic 2pi excitations of an optical transition in the dot. In the presence of a constant in-plane magnetic field, these optically induced geometric phases result in the effective rotation of the spin about the magnetic field axis and manifest as phase shifts in the spin quantum beat signal generated by two time-delayed circularly polarized optical pulses. The geometric phases generated in this manner more generally perform the role of a spin phase gate, proving potentially useful for quantum information applications.
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Affiliation(s)
- Erik D Kim
- The H. M. Randall Laboratory of Physics, The University of Michigan, Ann Arbor, Michigan 48109, USA
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11
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Fu KMC, Santori C, Barclay PE, Rogers LJ, Manson NB, Beausoleil RG. Observation of the dynamic Jahn-Teller effect in the excited states of nitrogen-vacancy centers in diamond. PHYSICAL REVIEW LETTERS 2009; 103:256404. [PMID: 20366270 DOI: 10.1103/physrevlett.103.256404] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Indexed: 05/29/2023]
Abstract
The optical transition linewidth and emission polarization of single nitrogen-vacancy (NV) centers are measured from 5 K to room temperature. Interexcited state population relaxation is shown to broaden the zero-phonon line and both the relaxation and linewidth are found to follow a T(5) dependence for T < 100 K. This dependence indicates that the dynamic Jahn-Teller effect is the dominant dephasing mechanism for the NV optical transitions at low temperatures.
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Affiliation(s)
- Kai-Mei C Fu
- Information and Quantum Systems Lab, Hewlett-Packard Laboratories, 1501 Page Mill Road, MS1123, Palo Alto, California 94304, USA.
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12
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Clark SM, Fu KMC, Zhang Q, Ladd TD, Stanley C, Yamamoto Y. Ultrafast optical spin echo for electron spins in semiconductors. PHYSICAL REVIEW LETTERS 2009; 102:247601. [PMID: 19659047 DOI: 10.1103/physrevlett.102.247601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Indexed: 05/28/2023]
Abstract
Spin-based quantum computing and magnetic resonance techniques rely on the ability to measure the coherence time T(2) of a spin system. We report on the experimental implementation of all-optical spin echo to determine the T(2) time of a semiconductor electron-spin system. We use three ultrafast optical pulses to rotate spins an arbitrary angle and measure an echo signal as the time between pulses is lengthened. Unlike previous spin-echo techniques using microwaves, ultrafast optical pulses allow clean T(2) measurements of systems with dephasing times (T_{2};{*}) fast in comparison to the time scale for microwave control. This demonstration provides a step toward ultrafast optical dynamic decoupling of spin-based qubits.
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Affiliation(s)
- Susan M Clark
- Edward L. Ginzton Laboratory, Stanford University, Stanford, California 94305-4088, USA.
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13
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Phelps C, Sweeney T, Cox RT, Wang H. Ultrafast coherent electron spin flip in a modulation-doped CdTe quantum well. PHYSICAL REVIEW LETTERS 2009; 102:237402. [PMID: 19658972 DOI: 10.1103/physrevlett.102.237402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Indexed: 05/28/2023]
Abstract
We report the experimental realization of coherent electron spin flip in a modulation-doped CdTe quantum well. Coherent spin rotation is realized with an off-resonant laser pulse, which induces a polarization-dependent optical Stark shift in the trion resonance. Complete electron spin flip is made possible by a laser pulse designed to avoid excessive excitations of nearby exciton resonances and minimizes detrimental many-body effects. These results demonstrate an effective approach for ultrafast optical spin control in a complex spin system.
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Affiliation(s)
- Carey Phelps
- Department of Physics, University of Oregon, Eugene, Oregon 97403, USA
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14
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Dubin F, Combescot M, Brennen GK, Melet R. Quantum control of a trapped electron spin in a quantum dot using photon polarization. PHYSICAL REVIEW LETTERS 2008; 101:217403. [PMID: 19113451 DOI: 10.1103/physrevlett.101.217403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Indexed: 05/27/2023]
Abstract
We present an original scheme to rotate at will one electron spin trapped in a quantum dot by just acting on pump-laser polarization: The quantum control is based on the virtual excitation of electron light-hole pairs with pi symmetry, as possibly done by using a single laser beam with a propagation axis slightly tilted with respect to a weak magnetic field. This allows us to fully control the effective axis of the electron spin rotation through the pump polarization. Our analysis shows that quantum dots with inverted valence states are ideal candidates for ultrafast, high-fidelity, all optical control.
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Affiliation(s)
- François Dubin
- Institut de Ciències Fotòniques, Mediterranean Technology Park, E-08860 Casteldefells, Spain
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15
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Complete quantum control of a single quantum dot spin using ultrafast optical pulses. Nature 2008; 456:218-21. [DOI: 10.1038/nature07530] [Citation(s) in RCA: 688] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 10/06/2008] [Indexed: 11/08/2022]
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Berezovsky J, Mikkelsen MH, Stoltz NG, Coldren LA, Awschalom DD. Picosecond Coherent Optical Manipulation of a Single Electron Spin in a Quantum Dot. Science 2008; 320:349-52. [DOI: 10.1126/science.1154798] [Citation(s) in RCA: 424] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- J. Berezovsky
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106, USA
| | - M. H. Mikkelsen
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106, USA
| | - N. G. Stoltz
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106, USA
| | - L. A. Coldren
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106, USA
| | - D. D. Awschalom
- Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106, USA
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