Precise Control of Local Spin States in an Adsorbed Magnetic Molecule with an STM Tip: Theoretical Insights from First-Principles-Based Simulation

Wang, Xiaoli; Yang, Longqing; Ye, LvZhou; Zheng, Xiao; Yan, YiJing

doi:10.1021/acs.jpclett.8b00808

Cited by 46 publications

(64 citation statements)

References 93 publications

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“…This is particularly important for the studies on precise control or fine-tuning of local quantum states in nanostructures. For instance, in the past few years, the competition between Kondo resonance and local spin excitations in magnetic molecular QDs has become a focus of experimental efforts [60]. Parks et al have demonstrated that, by stretching a molecular QD embedded in an MCBJ, the Kondo conductance peak is gradually split by enhancing the spin-orbit coupling [61].…”

Section: Scope Of the Reviewmentioning

confidence: 99%

Local temperatures out of equilibrium

2019

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The temperature of a physical system is operationally defined in physics as "that quantity which is measured by a thermometer" weakly coupled to, and at equilibrium with the system. This definition is unique only at global equilibrium in view of the zeroth law of thermodynamics: when the system and the thermometer have reached equilibrium, the "thermometer degrees of freedom" can be traced out and the temperature read by the thermometer can be uniquely assigned to the system. Unfortunately, such a procedure cannot be straightforwardly extended to a system out of equilibrium, where local excitations may be spatially inhomogeneous and the zeroth law of thermodynamics does not hold. With the advent of several experimental techniques that attempt to extract a single parameter characterizing the degree of local excitations of a (mesoscopic or nanoscale) system out of equilibrium, this issue is making a strong comeback to the forefront of research. In this paper, we will review the difficulties to define a unique temperature out of equilibrium, the majority of definitions that have been proposed so far, and discuss both their advantages and limitations. We will then examine a variety of experimental techniques developed for measuring the non-equilibrium local temperatures under various conditions. Finally we will discuss the physical implications of the notion of local temperature, and present the practical applications of such a concept in a variety of nanosystems out of equilibrium. Figure 4: (a) The product of the density of states η(E) times the global distribution function ϕ|ρ|ϕ forms a strongly pronounced peak at the expectation value of the global system energyĒ. (b) The logarithm of the local distribution function a|ρ|a (solid line) and the logarithm of a canonical distribution (dashed line) with the same local temperature for a harmonic chain. (a) and (b) are reprinted with permission from [74].

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Section: Scope Of the Reviewmentioning

confidence: 99%

Local temperatures out of equilibrium

2019

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“…71,72 The HEOM approach has been widely used to study a variety of static and dynamic properties of strongly correlated quantum impurity systems in and out of equilibrium. 62,63,[73][74][75][76][77][78][79] In the framework of the HEOM, the influence of the noninteracting leads on the impurity is fully captured by the hybridization functions, Γ α (ω) ≡ π k |t αk | 2 δ(ω − ǫ αk ). For numerical convenience, a Lorentzian form of Γ α (ω) = ∆αW 2 α (ω−Ωα) 2 +W 2 α is adopted, where ∆ α is the effec-tive coupling strength between the impurity and the αth lead, and Ω α and W α are the band center and width of the αth lead, respectively.…”

Section: Introductionmentioning

confidence: 99%

Effect of quantum resonances on local temperature in nonequilibrium open systems

Zeng

Zhang

et al. 2021

Phys. Rev. B

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Measuring local temperatures of open systems out of equilibrium is emerging as a novel approach to study the local thermodynamic properties of nanosystems. An operational protocol has been proposed to determine the local temperature by coupling a probe to the system and then minimizing the perturbation to a certain local observable of the probed system. In this paper, we first show that such a local temperature is unique for a single quantum impurity and the given local observable. We then extend this protocol to open systems consisting of multiple quantum impurities by proposing a local minimal perturbation condition (LMPC). The influence of quantum resonances on the local temperature is elucidated by both analytic and numerical results. In particular, we demonstrate that quantum resonances may give rise to strong oscillations of the local temperature along a multiimpurity chain under a thermal bias.

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“…The DFT+HEOM approach has been successfully applied to describe the Kondo spin-screening effect in magnetic atom adsorbed on the metal support. 22,42,43 Density functional theory calculation. The Perdew-Burke-Ernzerholf (PBE) generalized gradient approximation implemented in the Vienna ab initio simulation package 44 is employed, with the DFT-D3 method of Grimme 45 used to improve the description of van der Waals interactions.…”

Section: Methodsmentioning

confidence: 99%

Reaction on a Rink: Kondo-Enhanced Heterogeneous Single-Atom Catalysis

Li¹,

Gong²,

Zhuang³

et al. 2021

Preprint

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Boosting the efficiency of heterogeneous single-atom catalysts (SACs) by adjusting the microenvironment of the active atom has recently attracted enormous attention. However, attempts to tune the spin-spin interaction between the SAC and its microenvironment have remained rather scarce. Some interesting questions can be raised, among which a fundamental one is: can the surrounding environment influence the local spin state of an SAC, and if so, can such influence be utilized to enhance the catalytic activity? In this work, we explore such a possibility by investigating the thermochemical effect of Kondo screening of a local atomic spin by free electrons in the metal support. Inspired by the exothermicity of the spin-screening interaction, a novel approach to heterogeneous catalysis -- reaction on a rink (ROAR) -- is proposed. In contrast to the conventional notion of thermal catalytic reaction, lowering the temperature of metal support is predicted to result in a reduced reaction barrier. As a proof of concept, CO oxidation catalyzed by the Co@CoPc/Au(111) composite is scrutinized. By combining the density functional theory and a hierarchical equations of motion approach, it predicts that the existing s-d hybridization between the magnetic d orbital of Co adatom and the substrate metallic states in the transition state will lower the free energy barrier and accelerate the reaction rate. Furthermore, if the strength of s-d hybridization is enlarged, a more appreciable speedup will be achieved. This work highlights the potential usefulness of the spin degrees of freedom to heterogeneous single-atom catalysis, and our proposed ROAR approach could open up a new horizon for exploiting the role of atomic spin in chemical reactions.

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Precise Control of Local Spin States in an Adsorbed Magnetic Molecule with an STM Tip: Theoretical Insights from First-Principles-Based Simulation

Cited by 46 publications

References 93 publications

Local temperatures out of equilibrium

Local temperatures out of equilibrium

Effect of quantum resonances on local temperature in nonequilibrium open systems

Reaction on a Rink: Kondo-Enhanced Heterogeneous Single-Atom Catalysis

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