Photophysics of Nanometer Sized Metal Particles:  Electron−Phonon Coupling and Coherent Excitation of Breathing Vibrational Modes

2000 ◽  
Vol 104 (43) ◽  
pp. 9954-9965 ◽  
Author(s):  
Jose H. Hodak ◽  
Arnim Henglein ◽  
Gregory V. Hartland
Keyword(s):  
Metal Particles ◽  
Vibrational Modes ◽  
Phonon Coupling ◽  
Coherent Excitation ◽  
Electron Phonon Coupling

Direct evidence of the importance of electron-phonon coupling inLa2CuO4: Photoinduced ir-active vibrational modes

1987 ◽  
Vol 36 (13) ◽  
pp. 7252-7255 ◽  
Author(s):  
Y. H. Kim ◽  
A. J. Heeger ◽  
L. Acedo ◽  
G. Stucky ◽  
F. Wudl
Keyword(s):  
Direct Evidence ◽  
Vibrational Modes ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

Polaron Crystallization and the Metal–Insulator Transition

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3131-3136 ◽  
Author(s):  
P. Quémerais ◽  
S. Fratini
Keyword(s):  
Physical Mechanism ◽  
Insulator Transition ◽  
Vibrational Modes ◽  
Zero Temperature ◽  
Phonon Coupling ◽  
Metal Insulator Transition ◽  
Strong Electron ◽  
Metal Insulator ◽  
Electron Phonon Coupling ◽  
Polar Materials

The Crystallization of polarons at finite density, due to the long-range Coulomb forces — when no bipolarons can be formed — is discussed close to the metal–insulator transition (MIT). As a function of the density, the melting is examined at zero temperature. By calculating the quantum fluctuations of both the electron and the polarization, we show that at strong electron–phonon coupling the dissociation of the polarons at the MIT is favored, rather than the melting towards a polaron liquid. In this regime, we demonstrate, that an instability of the transverse vibrational modes of the polaron crystal occurs as the density increases. This provides a new physical mechanism for the MIT in polar materials, for which an experimental signature is predicted.

Neutron Spectroscopy of Superconducting Fullerides

1992 ◽  
Vol 270 ◽  
Author(s):  
Kosmas Prassides ◽  
Christos Christides ◽  
John Tomkinson ◽  
Matthew J. Rosseinsky ◽  
D. W. Murphy ◽  
...  
Keyword(s):  
Low Temperatures ◽  
High Energy ◽  
Inelastic Neutron ◽  
Low Energy ◽  
Vibrational Modes ◽  
Phonon Coupling ◽  
Phonon Spectra ◽  
Electron Phonon Coupling ◽  
Wide Range ◽  
Mechanism Of Superconductivity

ABSTRACTThe phonon spectra of pristine fullerene, superconducting K3C60 and saturation-doped Rb6C60 measured by inelastic neutron scatteringin the energy range 2.5 - 200 meV at low temperatures reveal substantial broadening of five-fold degenerate Hg intramolecular vibrational modes both in the low-energy radial and the high-energy tangential part of the spectrum. This provides strong evidence for a traditional phonon-mediated mechanism of superconductivity in the fullerides but with an electron-phonon coupling strength distributed over a wide range of energies (33-195 meV) as a result of the finite curvature of the fullerene spherical cage.

scholarly journals Photophysics and spectroscopy of metal particles

2000 ◽  
Vol 72 (1-2) ◽  
pp. 189-197 ◽  
Author(s):  
José H. Hodak ◽  
Arnim Henglein ◽  
Gregory V. Hartland
Keyword(s):  
Transient Absorption ◽  
Classical Mechanics ◽  
Transient Absorption Spectroscopy ◽  
Metal Particles ◽  
Characteristic Time Scale ◽  
Phonon Coupling ◽  
Particle Volume ◽  
Plasmon Band ◽  
Free Electron Density ◽  
Electron Phonon Coupling

This paper describes our recent work using ultrafast laser spectroscopy to examine the fundamental properties of metal particles. Two studies are presented. First, the characteristic time scale for electron-phonon coupling in Au particles with sizes between 2 and 120 nm has been examined by bleach recovery measurements. These experiments show that the coupling between the electrons and phonons is independent of particle size, to within the signal-to-noise of our experiments. We have also used transient absorption spectroscopy to examine the low-frequency "breathing" modes of the Au particles. These modes are impulsively excited by the rapid lattice heating that accompanies electron-phonon coupling. The breathing motion contributes to the transient absorption signal because the position of the plasmon band depends on the free electron density and, thus, the particle volume. The measured frequencies are inversely proportional to the radius, and almost exactly match the predictions of classical mechanics calculations for Au.

Observation of Core Phonon in Electron–Phonon Coupling in Au25 Nanoclusters

2021 ◽  
Vol 12 (6) ◽  
pp. 1690-1695
Author(s):  
Zhongyu Liu ◽  
Yingwei Li ◽  
Wonyong Shin ◽  
Rongchao Jin
Keyword(s):  
Phonon Coupling ◽  
Electron Phonon Coupling

scholarly journals Electron-phonon coupling in the magnetic Weyl semimetal ZrCo2Sn

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
I.Yu. Sklyadneva ◽  
R. Heid ◽  
P. M. Echenique ◽  
E. V. Chulkov
Keyword(s):  
Phonon Coupling ◽  
Weyl Semimetal ◽  
Electron Phonon Coupling

scholarly journals Dielectric screening in perovskite photovoltaics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rui Su ◽  
Zhaojian Xu ◽  
Jiang Wu ◽  
Deying Luo ◽  
Qin Hu ◽  
...  
Keyword(s):  
Open Circuit Voltage ◽  
Low Voltage ◽  
Power Conversion ◽  
Surface Recombination ◽  
Open Circuit ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Dielectric Screening ◽  
Perovskite Photovoltaic ◽  
Reduced Surface

AbstractThe performance of perovskite photovoltaics is fundamentally impeded by the presence of undesirable defects that contribute to non-radiative losses within the devices. Although mitigating these losses has been extensively reported by numerous passivation strategies, a detailed understanding of loss origins within the devices remains elusive. Here, we demonstrate that the defect capturing probability estimated by the capture cross-section is decreased by varying the dielectric response, producing the dielectric screening effect in the perovskite. The resulting perovskites also show reduced surface recombination and a weaker electron-phonon coupling. All of these boost the power conversion efficiency to 22.3% for an inverted perovskite photovoltaic device with a high open-circuit voltage of 1.25 V and a low voltage deficit of 0.37 V (a bandgap ~1.62 eV). Our results provide not only an in-depth understanding of the carrier capture processes in perovskites, but also a promising pathway for realizing highly efficient devices via dielectric regulation.

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