Ultrafast dynamics of electron-phonon coupling in a metal

Hwang, Choongyu; Zhang, Wentao; Kurashima, Koshi; Kaindl, Robert A.; Adachi, Tadashi; Koike, Yasuhiro; Lanzara, Alessandra

doi:10.1209/0295-5075/126/57001

Cited by 8 publications

(3 citation statements)

References 22 publications

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“…Lastly, we noted that the quadratic model reacts more strongly to a pump than the linear Holstein model, highlighting the importance of this mechanism in pump-probe experiments, e.g. [33]. Our results generally apply to light irradiated centrosymmetric crystals.…”

Section: Discussionsupporting

confidence: 62%

Phonon-induced disorder in dynamics of optically pumped metals from non-linear electron-phonon coupling

Sous,

Kloss,

Kennes

et al. 2020

Preprint

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The non-equilibrium dynamics of matter excited by light may produce electronic phases that do not exist in equilibrium, such as laser-induced high-Tc superconductivity. Here we simulate the dynamics of a metal driven at t = 0 by a pump that excites dipole-active vibrational modes that couple quadratically to electrons, and study the evolution of its electronic and vibrational observables. We provide evidence for enhancement of local electronic correlations, including double occupancy, accompanied by rapid loss of long-range spatial phase coherence. Concurrently, the onsite vibrational reduced density matrix evolves from its initial coherent state to one with a predominantly diagonal structure whose distribution qualitatively resembles the coherent state Poisson character. This rapid loss of coherence controls the electronic dynamics as the system evolves towards a correlated electron-phonon long-time state. We show that a simple model based on an effective disorder potential generated by the oscillator dephasing dynamics for the electrons provides an explanation for the flattening in momentum of electronic correlations. Our results provide a basis within which to understand correlation dynamics of vibrationally coupled electrons in pump-probe experiments.

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Section: Discussionsupporting

confidence: 62%

Phonon-induced disorder in dynamics of optically pumped metals from non-linear electron-phonon coupling

Sous,

Kloss,

Kennes

et al. 2020

Preprint

View full text Add to dashboard Cite

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“…The quadratic model reacts more strongly to a pump than the linear Holstein model, highlighting the importance of this mechanism in pump-probe experiments, e.g., ref. 48 . Questions such as the consideration of additional electron–vibration interactions consistent with inversion symmetry 20 , 49 , which may aid in the stabilization of a transient superconducting state, as well as how the electron–phonon steady state exposed in this work manifests experimentally are also important open challenges and call for the development of new tools for the study of out-of-equilibrium nonlinear electron–phonon problems.…”

Section: Discussionmentioning

confidence: 99%

Phonon-induced disorder in dynamics of optically pumped metals from nonlinear electron-phonon coupling

et al. 2021

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The non-equilibrium dynamics of matter excited by light may produce electronic phases, such as laser-induced high-transition-temperature superconductivity, that do not exist in equilibrium. Here we simulate the dynamics of a metal driven at initial time by a spatially uniform pump that excites dipole-active vibrational modes which couple nonlinearly to electrons. We provide evidence for rapid loss of spatial coherence, leading to emergent effective disorder in the dynamics, which arises in a system unitarily evolving under a translation-invariant Hamiltonian, and dominates the electronic behavior as the system evolves towards a correlated electron-phonon long-time state, possibly explaining why transient superconductivity is not observed. Our framework provides a basis within which to understand correlation dynamics in current pump-probe experiments of vibrationally coupled electrons, highlight the importance of the evolution of phase coherence, and demonstrate that pumped electron-phonon systems provide a means of realizing dynamically induced disorder in translation-invariant systems.

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“…Developments in experimental methods with ultra-fast dynamics (see, e.g., Refs. [1][2][3][4][5] and Refs. [6,7] for a review) have reinforced the interest in the theoretical modeling of electron-phonon interactions.…”

Section: Introductionmentioning

confidence: 99%

Finite-temperature density-matrix renormalization group method for electron-phonon systems: Thermodynamics and Holstein-polaron spectral functions

Jansen,

Bonča,

Heidrich-Meisner

2020

Preprint

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We investigate the thermodynamics and finite-temperature spectral functions of the Holstein polaron using a density-matrix renormalization group method. Our method combines purification and local basis optimization (LBO) as an efficient treatment of phonon modes. LBO is a scheme which relies on finding the optimal local basis by diagonalizing the local reduced density matrix. By transforming the state into this basis, one can truncate the local Hilbert space with a negligible loss of accuracy for a wide range of parameters. In this work, we focus on the crossover regime between large and small polarons of the Holstein model. Here, no analytical solution exists and we show that the thermal expectation values at low temperatures are independent of the phonon Hilbert space truncation provided the basis is chosen large enough. We then demonstrate that we can extract the electron spectral function and establish consistency with results from a finite-temperature Lanczos method. We additionally calculate the electron emission spectrum and the phonon spectral function and show that all the computations are significantly simplified by the local basis optimization. We observe that the electron emission spectrum shifts spectral weight to both lower frequencies and larger momenta as the temperature is increased. The phonon spectral function experiences a large broadening and the polaron peak at large momenta gets significantly flattened and merges almost completely into the free-phonon peak.

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Ultrafast dynamics of electron-phonon coupling in a metal

Cited by 8 publications

References 22 publications

Phonon-induced disorder in dynamics of optically pumped metals from non-linear electron-phonon coupling

Phonon-induced disorder in dynamics of optically pumped metals from non-linear electron-phonon coupling

Phonon-induced disorder in dynamics of optically pumped metals from nonlinear electron-phonon coupling

Finite-temperature density-matrix renormalization group method for electron-phonon systems: Thermodynamics and Holstein-polaron spectral functions

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