Lars Ehm

About

Lars Ehm is an Associate Professor and the Director of the Mineral Physics Institute at the Department of Geosciences at Stony Brook University. He holds a diploma and a Dr. rer. nat. degree from Christian-Albrechts-University Kiel, obtained in 2000 and 2003 respectively. His research interests focus on the structure-property relationships of Earth materials under extreme conditions. Ehm has a background that includes postdoctoral fellowships at the Geophysical Laboratory of the Carnegie Institution of Science and at the Mineral Physics Institute at Stony Brook University, where he later became a research faculty member before his current appointment. His work involves investigating the behavior of Earth materials at high pressures and temperatures, contributing to the understanding of phase transitions, amorphization, and other phenomena relevant to geosciences and planetary science.

Research topics

• Materials science
• Physics
• Optics
• Chemistry
• Condensed matter physics
• Atomic physics
• Nanotechnology
• Metallurgy
• Crystallography
• Thermodynamics

Selected publications

• Novel experimental setup for megahertz X-ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X-ray Free-Electron Laser (EuXFEL)

  Journal of Synchrotron Radiation · 2021 · 34 citations

  The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning expe…

  PublisherDOI

• Lattice Instability and Ultralow Lattice Thermal Conductivity of Layered PbIF

  ACS Applied Materials & Interfaces · 2022 · 28 citations

  materials for thermal energy applications.

  PublisherOA PDFDOI

• X-ray Free Electron Laser-Induced Synthesis of ε-Iron Nitride at High Pressures

  The Journal of Physical Chemistry Letters · 2021 · 20 citations

  , as deduced from its established equation of state (EOS). We thus demonstrate that the activation energy provided by intense X-ray exposures in an XFEL can be coupled with the source time structure to enable exploration of the time-dependence of reactions under high-pressure conditions.

  PublisherOA PDFDOI

• A MHz X-ray diffraction set-up for dynamic compression experiments in the diamond anvil cell

  Journal of Synchrotron Radiation · 2023-05-23 · 19 citations

  articleOpen access

  An experimental platform for dynamic diamond anvil cell (dDAC) research has been developed at the High Energy Density (HED) Instrument at the European X-ray Free Electron Laser (European XFEL). Advantage was taken of the high repetition rate of the European XFEL (up to 4.5 MHz) to collect pulse-resolved MHz X-ray diffraction data from samples as they are dynamically compressed at intermediate strain rates (≤10 3 s −1 ), where up to 352 diffraction images can be collected from a single pulse trai…

  PublisherOA PDFDOI

• Pressure-Induced Martensitic Phase Transition and Low Lattice Thermal Conductivity of SrClF

  The Journal of Physical Chemistry C · 2021-08-03 · 12 citations

  articleCorresponding

  In the present work, we report a pressure-induced martensitic phase transition for SrClF, which is analogous to BaClF and PbClF compounds. The predicted structural phase transition sequence for SrClF below 200 GPa is as follows: P4/nmm → Pmcn → P63/mmc with an increase in the coordination of a metal cation with structural motifs MCl5F4 [9] → MCl6F4 [10] → MCl6F5 [11], where M = Sr, Ba, and Pb, respectively. The martensitic phase transition is mainly driven by the cooperative displacive nature of…

  PublisherDOI

Recent grants

• Collaborative Proposal: ATREX - integrated open source data analysis software for mineral and environmental sciences

  NSF · $129k · 2014–2017

Frequent coauthors

• John B. Parise

  Stony Brook University

  97 shared

• F. Marc Michel

  Virginia Tech

  46 shared

• K. Knorr

  46 shared

• Sytle M. Antao

  University of Calgary

  39 shared

• Peter J. Chupas

  Stony Brook University

  35 shared

• G. Morard

  Institut des Sciences de la Terre

  34 shared

• Martin A. A. Schoonen

  Brookhaven National Laboratory

  28 shared

• Daniel R. Strongin

  Temple University

  28 shared

Education

• Other

  Christian-Albrechts-University Kiel

  2000

• Other

  Christian-Albrechts-University Kiel

  2003

• Other

  Geophysical Laboratory, Carnegie Institution of Science

  2005

• Other

  Mineral Physics Institute, Stony Brook University

  2007

• Other

  Mineral Physics Institute, Stony Brook University

  2018

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