Perspective: How to understand electronic friction

We present a protocol for the study of the dynamics and thermodynamics of quantum systems strongly coupled to a bath and subject to an external modulation. Our protocol quantifies the evolution of the system-bath composite by expanding the full density matrix as a series in the powers of the modulation rate, from which the functional form of work, heat and entropy rates can be obtained. Under slow driving, thermodynamic laws are established. The entropy production rate is positive and is found to be related to the excess work dissipated by friction, at least up to second order in the driving speed. As an example of the present methodology, we reproduce the results for the quantum thermodynamics of the driven resonance level model. We also emphasize that our formalism is quite general and allows for electron-electron interactions, which can give rise to exotic Kondo resonances appearing in thermodynamic quantities. arXiv:1808.08176v1 [cond-mat.stat-mech]

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“…For one electronic (or bosonic) bath, γ αν , Eq. (36), is positive definite 53,58 , so that the second law of thermodynamics is satisfied,…”

Section: Entropy Productionmentioning

confidence: 99%

“…thus establishing the first law of thermodynamics for the subsystem D. This result stems only from the the separability expressed by Eqs. (56)- (58). For slow driving we can further apply the expansion (Eq.…”

Section: System-bath Separationmentioning

confidence: 99%

Universal approach to quantum thermodynamics in the strong coupling regime

et al. 2018

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“…However, again one must assume either a quadratic Hamiltonian without electron-electron repulsion [35] or a mean-field electronic Hamiltonian [36]. (In a forthcoming article, we will show that the von Oppen and HGT expressions are identical at equilibrium [37]. )…”

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confidence: 99%

Born-Oppenheimer Dynamics, Electronic Friction, and the Inclusion of Electron-Electron Interactions

2017

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We present a universal expression for the electronic friction as felt by a set of classical nuclear degrees of freedom (DoF's) coupled to a manifold of quantum electronic DoF's; no assumptions are made regarding the nature of the electronic Hamiltonian and electron-electron repulsions are allowed. Our derivation is based on a quantum-classical Liouville equation (QCLE) for the coupled electronic-nuclear motion, followed by an adiabatic approximation whereby electronic transitions are assumed to equilibrate faster than nuclear movement. The resulting form of friction is completely general, but does reduce to previously published expressions for the quadratic Hamiltonian (i.e. Hamiltonians without electronic correlation). At equilibrium, the second fluctuation-dissipation theorem is satisfied and the frictional matrix is symmetric. To demonstrate the importance of electron-electron correlation, we study electronic friction within the Anderson-Holstein model, where a proper treatment of electron-electron interactions shows signatures of a Kondo resonance and a mean-field treatment is completely inadequate.Introduction.-The Born-Oppenheimer (BO) approximation is probably the most important framework underlying modern physics and chemistry. According to the BO approximation, for a system of nuclei and electrons, we split up the total Hamiltonian into the nuclear kinetic energy (T nuc ) and the electronic HamiltonianĤ:

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“…Conventional MD is based on two assumptions: (a) the Born–Oppenheimer (adiabatic) approximation which separates the electronic and nuclei motion, reducing the nuclei motion on a single adiabatic potential energy surface (PES) and (b) the classical treatment of the nuclei. Processes such as electron transfer, charge transport, electronic friction at metal surfaces and nonradiative decay after photoexcitation often involve multiple PESs, with nonadiabatic (NA) transitions among them. In addition, for systems containing small mass elements, for example, hydrogen, zero‐point motion and tunneling effects may not be ignored and as a result require a quantum mechanical description of the nuclei .…”

Section: Introductionmentioning

confidence: 99%

Ab initio nonadiabatic molecular dynamics investigations on the excited carriers in condensed matter systems

Zheng

Chu

Zhao

et al. 2019

WIREs Comput Mol Sci

247

258

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The ultrafast dynamics of photoexcited charge carriers in condensed matter systems play an important role in optoelectronics and solar energy conversion. Yet it is challenging to understand such multidimensional dynamics at the atomic scale. Combining the real‐time time‐dependent density functional theory with fewest‐switches surface hopping scheme, we develop time‐dependent ab initio nonadiabatic molecular dynamics (NAMD) code Hefei‐NAMD to simulate the excited carrier dynamics in condensed matter systems. Using this method, we have investigated the interfacial charge transfer dynamics, the electron–hole recombination dynamics, and the excited spin‐polarized hole dynamics in different condensed matter systems. The time‐dependent dynamics of excited carriers are studied in energy, real and momentum spaces. In addition, the coupling of the excited carriers with phonons, defects and molecular adsorptions are investigated. The state‐of‐art NAMD studies provide unique insights to understand the ultrafast dynamics of the excited carriers in different condensed matter systems at the atomic scale. This article is categorized under: Structure and Mechanism > Computational Materials Science Molecular and Statistical Mechanics > Molecular Dynamics and Monte‐Carlo Methods Electronic Structure Theory > Ab Initio Electronic Structure Methods Software > Simulation Methods

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Perspective: How to understand electronic friction

Cited by 87 publications

References 120 publications

Universal approach to quantum thermodynamics in the strong coupling regime

Universal approach to quantum thermodynamics in the strong coupling regime

Born-Oppenheimer Dynamics, Electronic Friction, and the Inclusion of Electron-Electron Interactions

Ab initio nonadiabatic molecular dynamics investigations on the excited carriers in condensed matter systems

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