scholarly journals Nonequilibrium Band Occupation and Optical Response of Gold After Ultrafast XUV Excitation

2021 ◽  
Author(s):  
Pascal D. Ndione ◽  
Sebastian T. Weber ◽  
Dirk O. Gericke ◽  
Baerbel Rethfeld
Keyword(s):  
Theoretical Model ◽  
Large Range ◽  
Optical Response ◽  
Free Electron Lasers ◽  
Phonon Coupling ◽  
Energy Bands ◽  
Short Pulses ◽  
Solid Gold ◽  
Electron Phonon Coupling ◽  
Far From Equilibrium

Abstract Free electron lasers offer unique properties to study matter in states far from equilibrium as they combine short pulses with a large range of photon energies. In particular, the possibility to excite core states drives new relaxation pathways that, in turn, also change the properties of the optically and chemically active electrons. Here, we present a theoretical model for the dynamics of the nonequilibrium occupation of the different energy bands in solid gold driven by exciting deep core states. The resulting optical response is in excellent agreement with recent measurements and, combined with our model, provides a quantitative benchmark for the description of electron-phonon coupling in strongly driven gold. Focusing on sub-picosecond time scales, we find essential differences between the dynamics induced by XUV and visible light.

scholarly journals Collective modes in excitonic insulators: Effects of electron-phonon coupling and signatures in the optical response

2020 ◽  
Vol 101 (19) ◽  
Author(s):  
Yuta Murakami ◽  
Denis Golež ◽  
Tatsuya Kaneko ◽  
Akihisa Koga ◽  
Andrew J. Millis ◽  
...  
Keyword(s):  
Optical Response ◽  
Collective Modes ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

Velocity renormalization in graphene: The role of trigonal warping and electron–phonon coupling effects

2017 ◽  
Vol 31 (30) ◽  
pp. 1750235 ◽  
Author(s):  
B. S. Kandemir ◽  
N. Gökçek
Keyword(s):  
Analytical Solution ◽  
Fermi Velocity ◽  
Combined Effects ◽  
Phonon Coupling ◽  
Strong Anisotropy ◽  
Energy Bands ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Trigonal Warping

We investigate the combined effects of trigonal warping and electron–phonon interactions on the renormalization of the Fermi velocity in graphene. We present an analytical solution to the associated Fröhlich Hamiltonian describing the interaction of doubly degenerate-optical phonon modes of graphene with electrons in the presence of trigonal warp within the framework of Lee–Low–Pines theory. On the basis of our model, it is analytically shown that in addition to its renormalization, Fermi velocity exhibits strong anisotropy due to the trigonal warping. It is also found that in the regime where the trigonal warp starts, distortion of energy bands emerges due to electron–phonon coupling, and the bands exhibit strong anisotropy.

Polarons and strong electron-phonon coupling in the optical response of La{2-x}SrxCuO4SrxCuO4

1997 ◽  
Vol 10 (4) ◽  
pp. 299-303 ◽  
Author(s):  
H. J. Kaufmann ◽  
E. K. H. Salje ◽  
Y. Yagil ◽  
O. V. Dolgov
Keyword(s):  
Optical Response ◽  
Phonon Coupling ◽  
Strong Electron ◽  
Electron Phonon Coupling

scholarly journals Evidence for strong electron-phonon coupling and polarons in the optical response of La2−xSrxCuO4

1997 ◽  
Vol 279 (1-2) ◽  
pp. 113-121 ◽  
Author(s):  
Oleg V. Dolgov ◽  
Holger J. Kaufmann ◽  
Ekhard K.H. Salje ◽  
Yoad Yagil
Keyword(s):  
Optical Response ◽  
Phonon Coupling ◽  
Strong Electron ◽  
Electron Phonon Coupling

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.

scholarly journals Structural phase transition and superconductivity hierarchy in 1T-TaS2 under pressure up to 100 GPa

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Qing Dong ◽  
Quanjun Li ◽  
Shujia Li ◽  
Xuhan Shi ◽  
Shifeng Niu ◽  
...  
Keyword(s):  
Structural Phase ◽  
Transition Metal Dichalcogenides ◽  
Phonon Coupling ◽  
Structural Phase Transitions ◽  
Strong Electron ◽  
Electron Phonon Coupling ◽  
Increasing Trend ◽  
Metal Dichalcogenides ◽  
Dome Shape ◽  
Enhanced Superconductivity

AbstractThe adoption of high pressure not only reinforces the comprehension of the structure and exotic electronic states of transition metal dichalcogenides (TMDs) but also promotes the discovery of intriguing phenomena. Here, 1T-TaS2 was investigated up to 100 GPa, and re-enhanced superconductivity was found with structural phase transitions. The discovered I4/mmm TaS2 presents strong electron–phonon coupling, revealing a good superconductivity of the nonlayered structure. The P–T phase diagram shows a dome shape centered at ~20 GPa, which is attributed to the distortion of the 1T structure. Accompanied by the transition to nonlayered structure above 44.5 GPa, the superconducting critical temperature shows an increasing trend and reaches ~7 K at the highest studied pressure, presenting superior superconductivity compared to the original layered structure. It is unexpected that the pressure-induced re-enhanced superconductivity was observed in TMDs, and the transition from a superconductor with complicated electron-pairing mechanism to a phonon-mediated superconductor would expand the field of pressure-modified superconductivity.

Ab Initio Study of the Electron–Phonon Coupling in Ultrathin Al Layers

2021 ◽  
Vol 203 (1-2) ◽  
pp. 180-193
Author(s):  
S. Giaremis ◽  
Ph. Komninou ◽  
Th. Karakostas ◽  
J. Kioseoglou
Keyword(s):  
Ab Initio ◽  
Ab Initio Study ◽  
Phonon Coupling ◽  
Electron Phonon Coupling
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