Electron-phonon interaction within classical molecular dynamics

Tamm, Artur; Samolyuk, German D.; Correa, Alfredo A.; Klintenberg, Mattias; Aabloo, Alvo; Caro, A.

doi:10.1103/physrevb.94.024305

Cited by 17 publications

(11 citation statements)

References 25 publications

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“…Furthermore, we observe that different branches have different lifetimes. This rich behavior not only emerges from the principles utilized to construct the forces in the Langevin model, but it is also in qualitative agreement with more elaborate quantum mechanical treatments of the coupling [15]. The perfect crystal helps in the interpretation of friction forces (second term in Eq.…”

supporting

confidence: 63%

“…In the presence of collective modes such as phonons in solids, simple Langevin dynamics as a model of an electronic bath fails in a fundamental way; as it damps all motion, including rigid translation of the whole (ions plus electrons) solid. Moreover, in a recent study [15] we showed that the scalar Langevin model introduces the same lifetime for all phonon modes see Fig. 4 in Ref.…”

mentioning

confidence: 71%

“…We use atomic-like density of Ni to construct the weighting function and obtain an approximation for the coupling parameters {α I } I between the ionic and electronic systems from ab initio TDDFT calculations [30]. These parameters define the model fully for a specific material and are described in our previous work [15]. (Other methods can be utilized to fit or obtain the coupling parameters ab initio, such as surface hopping [31], adiabatic perturbation theory [32] or linear response [33].)…”

mentioning

confidence: 99%

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Langevin Dynamics with Spatial Correlations as a Model for Electron-Phonon Coupling

Tamm

Caro

et al. 2018

Phys. Rev. Lett.

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Stochastic Langevin dynamics has been traditionally used as a tool to describe nonequilibrium processes. When utilized in systems with collective modes, traditional Langevin dynamics relaxes all modes indiscriminately, regardless of their wavelength. We propose a generalization of Langevin dynamics that can capture a differential coupling between collective modes and the bath, by introducing spatial correlations in the random forces. This allows modeling the electronic subsystem in a metal as a generalized Langevin bath endowed with a concept of locality, greatly improving the capabilities of the two-temperature model. The specific form proposed here for the spatial correlations produces a physical wave-vector and polarization dependency of the relaxation produced by the electron-phonon coupling in a solid. We show that the resulting model can be used for describing the path to equilibration of ions and electrons and also as a thermostat to sample the equilibrium canonical ensemble. By extension, the family of models presented here can be applied in general to any dense system, solids, alloys, and dense plasmas. As an example, we apply the model to study the nonequilibrium dynamics of an electron-ion two-temperature Ni crystal.

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confidence: 63%

mentioning

confidence: 71%

mentioning

confidence: 99%

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Langevin Dynamics with Spatial Correlations as a Model for Electron-Phonon Coupling

Tamm

Caro

et al. 2018

Phys. Rev. Lett.

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“…Additional work on the non-adiabatic equations of motion led us to propose modifications to the Langevin equations that capture in detail the wave-vector qdependence of the phonon lifetimes, in agreement with quantum mechanics calculations [31]. The modifications are based on a local view of the e-ph interaction obtained as the low-velocity limit of the stopping power of a moving ion.…”

Section: Introductionmentioning

confidence: 73%

Role of electrons in collision cascades in solids. II. Molecular dynamics

Tamm

Caro

et al. 2019

Phys. Rev. B

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We present a model for the role of electrons in collision cascades in solids in which the coupling between ions and electrons is calculated using first-principles models and introduced into the classical ion equations of motion using our modified Langevin dynamics [Tamm et al. Phys. Rev. Lett. 120, 185501 (2018)]. This model gives a full picture of the entire collision process, from the ballistic to the thermal phases of a cascade, giving a detailed representation of the energy exchange between ions and electrons until their final thermalization, removing in this way some ad hoc assumptions used in the state-of-the-art two-temperature model. This work is separated into two papers; Part I [Caro et al. Phys. Rev. B (in press)] reports on the ab initio methodology used to translate stopping power into the parametrized dissipation function; this Part II applies the non-adiabatic ion dynamics using the dissipation functions developed in Part I to specific collision cascade events.

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“…TTM-MD has proved to be successful in predicting the thermal transport in metallic systems. [66][67][68][69] Phonon-phonon non-equilibrium in single materials In addition to local thermal non-equilibrium between electrons and phonons, different phonon branches in a single material can also be driven into thermal non-equilibrium. The observation of non-p-p equilibrium dates back to 1980's when the "hot phonon bottleneck" was observed for photoexcited semiconductors.…”

Section: Two-temperature Molecular Dynamicsmentioning

confidence: 99%

Non-Equilibrium Thermal Transport: A Review of Applications and Simulation Approaches

Lu¹,

Ruan²

2019

ES Energy Environ.

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As modern electronics shrink into nano-scale with increasing power consumption, thermal management inevitably becomes an important issue. Contrary to the conventional view of a single "apparent" temperature profile, electrons and different modes of phonons usually have different temperatures under many circumstances. This local thermal non-equilibrium appears widely in applications such as laser-matter interaction, hot electron cooling in solar cells, thermal transport across metal-insulator and semiconductor-semiconductor interfaces, etc. The resolved temperature profiles usually deviate significantly from the apparent temperature and have non-negligible effects on the measurement and interpretation of thermal properties and performance. Regardless, this phenomenon has been largely overlooked in early studies and has only started to attract attentions in the recent decades. In this work, we will review the background and research efforts on non-equilibrium thermal transport. The applications where non-equilibrium thermal transport is significant, and the corresponding simulation approaches, focused on two-temperature model, molecular dynamics, Boltzmann transport equations, and multi-temperature model, are reviewed.

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Electron-phonon interaction within classical molecular dynamics

Cited by 17 publications

References 25 publications

Langevin Dynamics with Spatial Correlations as a Model for Electron-Phonon Coupling

Langevin Dynamics with Spatial Correlations as a Model for Electron-Phonon Coupling

Role of electrons in collision cascades in solids. II. Molecular dynamics

Non-Equilibrium Thermal Transport: A Review of Applications and Simulation Approaches

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