Methods

A variety of analytical instruments, micro sample preparation equipment, and high-pressure devices for high pressure research are available at the Shim Lab. We utilize high-pressure and analytical facilities located on the ASU campus and in national laboratories.

Laser-heated diamond anvil cell

In diamond-anvil cells, materials are compressed between two gem-quality diamond anvils to generate extremely high pressures ranging from 1-5,000,000 bars. Diamond is the strongest material known to date and transmits a wide range of electromagnetic radiation, including X-rays, infrared, and visible light. These properties allow us to conduct in situ diffraction or spectroscopy measurements under high-pressure and high-temperature conditions. Laser heating systems are employed to raise the temperature of the samples in the diamond-anvil cells to temperatures between 1,000-5,000 K. The temperature can be estimated by analyzing the black-body radiation of the samples. Our lab has both fiber optic laser (1,070 nm) and CO2 laser (10,000 nm) heating systems at our disposal. Recent examples: Ko et al. (2022, Nature), Fu et al. (2023, Nature)

Hydrogen gas loading system

The gas loading system in our lab is capable of loading a variety of gases into diamond-anvil cells, including hydrogen, helium, neon, oxygen, and gas mixtures. This allows us to conduct high-pressure experiments on the chemical reactions between volatiles and silicates/metals. Recent examples: Fu et al. (2023, Nature), Horn et al. (2023, Planetary Science Journal).

Multi-anvil press

A multi-anvil press allows for the synthesis of a large amount of sample at 0-28 GPa. Two 1100-ton multi-anvil presses are available at ASU (PI: Leinenweber). Four more presses are being installed at FORCE (Facility for Open Research in a Compressional Environment), ASU. A 6000-ton press will allow us to study petrology of the Earth's lower mantle and alloying at the Martian core. A 1500-ton DIA type press will enable large-volume experiments to the pressure conditions of the lowermost mantle. Recent examples: Kulka et al. (2020, Minerals), Chen et al. (2020, Am Min).

Dynamic compression

We conduct dynamic compression of silicates and metals to understand the atomic-scale structures and the properties of the melts at extreme pressures and temperatures.  We use laser systems for dynamic compression at LCLS-XFEL. Recent examples: Hwang et al. (2020; Science Advances), Morard et al. (2020: PNAS).

Synchrotron 

Synchrotron facilities provide extremely bright X-ray beams for diffraction and spectroscopy measurements in diamond-anvil cells. We perform diffraction and spectroscopy at synchrotron facilities (Advanced Phton Source, Advanced Light Source, and National Synchrotron Light Source). Recent examples: Ko et al. (2022, Nature), Fu et al. (2023, Nature), Shim et al. (2017, PNAS).

X-ray Free Electron Laser

X-ray free electron laser sources provide extremely bright X-ray pulses with very high time resolution. We have conducted both dynamic and static experiments at XFEL sources (Linac Coherent Light Source at Stanford University and Pohang Accelerator Laboratory X-ray Free Electron Laser). ASU's compact XFEL source will enable us to conduct some unique experiments in near future. Recent examples: Hwang et al. (2020; Science Advances), Morard et al. (2020: PNAS).

Raman spectroscopy

The phonon spectra allow for phase identification and estimation of thermodynamic properties. Raman spectroscopy is particularly powerful for studying icy materials (e.g., H2O, NH3, CH4, and CO2) and volatile components in materials. Our system is capable of 2D scan of the samples (both diamond-anvil cell and multi-anvil press) as well as in situ high pressure measurements in diamond-anvil cell. Recent examples: Allen-Sutter et al. (2020, PSJ), Ko et al. (2022, GRL).

Electron Microscopy

Aberration corrected electron microscopy provides exciting new opportunities to measure chemical properties of extremely small samples with atomic to nanometer scale spatial resolution with superb spectral resolutions (EDX and EELS). We have some exciting new STEM system in LeRoy Eyring Center for Solid State Science at ASU. Recent examples: Shim et al. (2017, PNAS), Kim et al. (2021, Nature Astronomy).

Secondary Ion Mass Spectrometry

Secondary ion mass spectrometry allows for the measurements of isotopic ratios and volatile contents of the samples synthesized at high pressure. ASU has a secondary ion mass spectrometry system and a NanoSIMS instrument. Recent examples: Nisr et al. (2020; PNAS).

Density functional theory

Although high-pressure techniques have facilitated a plethora of remarkable in situ measurements, the resulting data quality and coverage are often incomplete. This shortcoming can be resolved by conducting experimental measurements in conjunction with density functional theory calculations. Recent examples: Nisr et al. (2020; PNAS), Piet et al. (2023; GRL).