Alexander H. Reid

SLAC National Accelerator Laboratory

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Xijie Wang

Zhejiang University

H. A. Dürr

Uppsala University

Stephen Weathersby

SLAC National Accelerator Laboratory

Xiaozhe Shen

SLAC National Accelerator Laboratory

W. F. Schlotter

Coherent (United States)

Renkai Li

University of Hong Kong

Xiaozhe Shen

SLAC National Accelerator Laboratory

Ming‐Fu Lin

SLAC National Accelerator Laboratory

Georgi L. Dakovski

Linac Coherent Light Source

Aaron M. Lindenberg

Stanford University

Cooperative Institutions

SLAC National Accelerator Laboratory

385

Stanford University

245

Menlo School

181

Lawrence Berkeley National Laboratory

162

Linac Coherent Light Source

157

University of California, Berkeley

103

Stanford Synchrotron Radiation Lightsource

Deutsches Elektronen-Synchrotron DESY

Argonne National Laboratory

Brookhaven National Laboratory

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Nonequilibrium electron and lattice dynamics of strongly correlated Bi ₂ Sr ₂ CaCu ₂ O _8+δ single crystals

Science Advances (2018)

Tatiana Konstantinova J. D. Rameau Alexander H. Reid Omadillo Abdurazakov Lijun Wu

The interplay between the electronic and lattice degrees of freedom in nonequilibrium states of strongly correlated systems has been debated for decades. Although progress has been made in establishing a hierarchy of electronic interactions with the use of time-resolved techniques, the role of the phonons often remains in dispute, a situation highlighting the need for tools that directly probe the lattice. We present the first combined megaelectron volt ultrafast electron diffraction and time- and angle-resolved photoemission spectroscopy study of optimally doped Bi2Sr2CaCu2O8+δ. Quantitative analysis of the lattice and electron subsystems' dynamics provides a unified picture of nonequilibrium electron-phonon interactions in the cuprates beyond the N-temperature model. The work provides new insights on the specific phonon branches involved in the nonequilibrium heat dissipation from the high-energy Cu-O bond stretching "hot" phonons to the lowest-energy acoustic phonons with correlated atomic motion along the <110> crystal directions and their characteristic time scales. It reveals a highly nonthermal phonon population during the first several picoseconds after the photoexcitation. The approach, taking advantage of the distinct nature of electrons and photons as probes, is applicable for studying energy relaxation in other strongly correlated electron systems.

Lattice (music)

10.1126/sciadv.aap7427

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Citations (67)

Direct observation of strong momentum-dependent electron-phonon coupling in a metal

Science Advances (2024)

Mianzhen Mo Artur Tamm Erki Metsanurk Zhijiang Chen Ling Wang

Phonon scattering in metals is one of the most fundamental processes in materials science. However, understanding such processes has remained challenging and requires detailed information on interactions between phonons and electrons. We use an ultrafast electron diffuse scattering technique to resolve the nonequilibrium phonon dynamics in femtosecond–laser-excited tungsten in both time and momentum. We determine transient populations of phonon modes which show strong momentum dependence initiated by electron-phonon coupling. For phonons near Brillouin zone border, we observe a transient rise in their population on a timescale of approximately 1 picosecond driven by the strong electron-phonon coupling, followed by a slow decay on a timescale of approximately 8 picosecond governed by the weaker phonon-phonon relaxation process. We find that the exceptional harmonicity of tungsten is needed for isolating the two processes, resulting in long-lived nonequilibrium phonons in a pure metal. Our finding highlights that electron-phonon scattering can be the determinant factor in the phonon thermal transport of metals.

Picosecond

Phonon scattering

10.1126/sciadv.adk9051

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X-ray Resonant Magnetic Scattering of Fe$_{3}$O$_{4}$ Nanoparticles

Bulletin of the American Physical Society (2014)

Dalton Griner Yanping Cai Matea Trevino Karine Chesnel Roger G. Harrison

Source

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On ultrafast x-ray scattering methods for magnetism

Advances in Physics X (2024)

Rajan Plumley Sathya R. Chitturi Peng Cheng Tadesse A. Assefa Nicolas Burdet

With the introduction of x-ray free electron laser sources around the world, new scientific approaches for visualizing matter at fundamental length and time-scales have become possible. As it relates to magnetism and 'magnetic-type' systems, advanced scattering methods are being developed for studying ultrafast magnetic responses on the time-scales at which they occur. We describe three capabilities which have the potential to seed new directions in this area and present

Magnetism

Electron scattering

10.1080/23746149.2024.2423935

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Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

Review of Scientific Instruments (2016)

Mianzhen Mo Xiaozhe Shen Zhijiang Chen Renkai Li M. Dunning

We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 μm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined. This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime.

Ultrafast electron diffraction

State of matter

Warm dense matter

Pulse duration

10.1063/1.4960070

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Development of a THz Pump MeV Ultrafast Electron Diffraction Probe Apparatus

Conference on Lasers and Electro-Optics (2018)

Benjamin K. Ofori-Okai Matthias C. Hoffmann Alexander H. Reid Renkai Li Xiaozhe Shen

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text B. K. Ofori-Okai, M. C. Hoffmann, A. H. Reid, R. Li, X. Shen, J. Yang, Q. Zheng, S. J. Park, E. M. Mannenbach, S. P. Weathersby, S. Edstrom, W. Polzin, A. M. Lindenberg, S. H. Glenzer, and X. Wang, "Development of a THz Pump MeV Ultrafast Electron Diffraction Probe Apparatus," in Conference on Lasers and Electro-Optics, OSA Technical Digest (online) (Optica Publishing Group, 2018), paper SM3A.1. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

10.1364/cleo_si.2018.sm3a.1

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Femtosecond X-ray magnetic circular dichroism absorption spectroscopy at an X-ray free electron laser

Review of Scientific Instruments (2016)

Daniel J. Higley Konstantin Hirsch Georgi L. Dakovski Emmanuelle Jal Edwin Yuan

X-ray magnetic circular dichroism spectroscopy using an X-ray free electron laser is demonstrated with spectra over the Fe L3,2-edges. The high brightness of the X-ray free electron laser combined with high accuracy detection of incident and transmitted X-rays enables ultrafast X-ray magnetic circular dichroism studies of unprecedented sensitivity. This new capability is applied to a study of all-optical magnetic switching dynamics of Fe and Gd magnetic sublattices in a GdFeCo thin film above its magnetization compensation temperature.

Free-electron laser

Vibrational Circular Dichroism

10.1063/1.4944410

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Emergent super-antiferromagnetic correlations in monolayers of Fe3O4 nanoparticles throughout the superparamagnetic blocking transition

arXiv (Cornell University) (2023)

Johnathon Rackham Brittni Pratt Dalton Griner Dallin L. Smith Yanping Cai

We report nanoscale inter-particle magnetic orderings in self-assemblies of Fe3O4 nanoparticles (NPs), and the emergence of inter-particle antiferromagnetic (AF) (super-antiferromagnetic) correlations near the coercive field at low temperature. The magnetic ordering is probed via x-ray resonant magnetic scattering (XRMS), with the x-ray energy tuned to the Fe-L3 edge and using circular polarized light. By exploiting dichroic effects, a magnetic scattering signal is isolated from the charge scattering signal. The magnetic signal informs about nanoscale spatial orderings at various stages throughout the magnetization process and at various temperatures throughout the superparamagnetic blocking transition, for two different sizes of NPs, 5 and 11 nm, with blocking temperatures TB of 28 K and 170 K, respectively. At 300 K, while the magnetometry data essentially shows superparamagnetism and absence of hysteresis for both particle sizes, the XRMS data reveals the presence of non-zero (up to 9/100) inter-particle AF couplings when the applied field is released to zero for the 11 nm NPs. These AF couplings are drastically amplified when the NPs are cooled down below TB and reach up to 12/100 for the 5 nm NPs and 48/100 for the 11 nm NPs, near the coercive point. The data suggests that the particle size affects the prevalence of the AF couplings: compared to ferromagnetic (F) couplings, the relative prevalence of AF couplings at the coercive point increases from a factor ~ 1.6 to 3.8 when the NP size increases from 5 to 11 nm.

Superparamagnetism

Hysteresis

10.48550/arxiv.2306.11994

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High-sensitivity X-ray Optical Cross-Correlator for Next Generation Free-Electron Lasers

Conference on Lasers and Electro-Optics (2019)

Stefan Droste L. Shen Vaughn E. White Elizabeth Diaz-Jacobo Ryan Coffee

We designed a novel X-ray arrival time monitor that cross-correlates X-ray and 1550 nm optical pulses used in state-of-the-art femtosecond timing distribution systems. We exploit an interferometric detection scheme and etalon effects in thin-film Germanium to achieve unprecedented high sensitivity to soft X-rays.

10.1364/cleo_si.2019.sf3i.7

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Response of fs-Laser-Irradiated Diamond by Ultrafast Electron Diffraction

The Journal of Physical Chemistry C (2024)

Franky Bernal Erika J. Riffe Shane W. Devlin Sébastien Hamel Rebecca Lindsey

Structural details of the proposed solid–liquid phase transition of carbon have remained elusive, despite years of study. While it is theorized that novel carbon materials form from a liquid precursor, experimental studies have lacked the temporal and spatial resolution necessary to fully characterize the purported liquid state. Here we utilize megaelectronvolt-ultrafast electron diffraction (MeV-UED) to study laser irradiated submicron diamond thin films in a pump–probe scheme with picosecond time resolution to visualize potential structural changes of excited diamond. We probe the structure of diamond using a combination of fluences (13, 40 J/cm2) and time delays (10, 25, 100 ps), but observe negligible changes in the static diffraction pattern of diamond and an overall decrease in diffraction intensity up to 100 ps after the excitation pulse. We thus conclude that no appreciable amount of liquid or graphitized carbon is present and highlight the structural resilience of bulk diamond to intense 800 nm ultrafast laser pulses.

Ultrafast electron diffraction

Picosecond

Carbon fibers

10.1021/acs.jpcc.4c05999

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