Timothy Strobel subjects materials to high-pressures to understand chemical processes  and interactions, and to create new, advanced energy-related materials.

For instance, silicon is the second most abundant element in the Earth’s crust and a mainstay of the electronics industry. But normal silicon is not optimal for solar energy. In its conventional crystalline form, silicon is relatively inefficient at absorbing the wavelengths most prevalent in sunlight.  Strobel made a discovery that may turn things around.  Using the high-pressure techniques pioneered at Carnegie, he created a novel form of silicon with its atoms arranged in a cage-like structure. Unlike normal silicon, this new form has near-ideal properties for absorbing sunlight, and could potentially usher in an entirely new generation of solar cells.

Understanding the chemical reactions that can create tiny molecular cages that hold other “guest” molecules—structures called clathrates—is key to creating a new generation of electronic devices and possible energy materials.  Strobel and team are the first to use high-pressure synthesis to create a stable clathrate of sodium (Na) and silicon (Si)—the least understood system of the so-called group 14 clathrates. Strobel also created a new clathrate of hydrogen sulfide (H2S) and molecular hydrogen (H2). Both findings open the door for major advances in materials science.

In addition to these experiments, Strobel and team performed calculations to predict how the materials would behave. Calculations and experiments revealed that sodium clathrates are thermodynamically stable at high pressure. The consistency suggests that scientists can use theoretical calculations to predict new synthesis routes for other compounds.

In other work, a team including Strobel reported the synthesis of an ionic semiconductor Mg2C, under high-pressure, high-temperature conditions, which is fully recoverable to ambient conditions. Semiconductors are substances with electrical conductivity between insulators and metals used in electronic circuits.

 Strobel received his B.S. and Ph. D. from the Colorado School of Mines in 2004 and 2008 respectively. In 2008 he became a Carnegie postdoctoral fellow, where he became fascinated by high-pressure science. In 2010 he was appointed research scientist, then staff scientist in 2011. For more see the Strobel lab

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Stock image of the transition metals section of the periodic table
July 1, 2020

Washington, DC— You’ve heard the expression form follows function? In materials science, function follows form.

New research by Carnegie’s Olivier Gagné and collaborator Frank Hawthorne of the University of Manitoba categorizes the causes of structural asymmetry, some surprising, which underpin useful properties of crystals, including ferroelectricity, photoluminescence, and photovoltaic ability. Their findings are published this week as a lead article in the International Union of Crystallography Journal.

“Understanding how different bond arrangements convey various useful attributes is central to the materials sciences” explained

April 15, 2020

Washington, DC— Carnegie mineralogist Robert Hazen was inducted last month as a foreign member of the Russian Academy of Sciences—the nation’s highest-level scientific society, originally founded by Peter the Great. This is a rare honor for an American researcher.

The ceremony, originally scheduled for the end of March, was postponed by the COVID-19 pandemic.

A Staff Scientist at Carnegie’s Earth and Planets Laboratory, Hazen pioneered the concept of mineral evolution—linking an explosion in mineral diversity to the rise of life on Earth—and developed  the idea of mineral ecology—which analyzes the spatial distribution of the

Carbon-boron clathrate cage with strontium inside, courtesy Tim Strobel
January 10, 2020

Washington, DC— A long-sought-after class of “superdiamond” carbon-based materials with tunable mechanical and electronic properties was predicted and synthesized by Carnegie’s Li Zhu and Timothy Strobel. Their work is published by Science Advances.

Carbon is the fourth-most-abundant element in the universe and is fundamental to life as we know it. It is unrivaled in its ability to form stable structures, both alone and with other elements.

A material’s properties are determined by how its atoms are bonded and the structural arrangements that these bonds create. For carbon-based materials, the type of bonding makes the difference between the

December 16, 2019

Washington, DC— Every school child learns about the water cycle—evaporation, condensation, precipitation, and collection. But what if there were a deep Earth component of this process happening on geologic timescales that makes our planet ideal for sustaining life as we know it?

New work published in the Proceedings of the National Academy of Sciences by Carnegie’s Yanhao Lin and Michael Walter—along with former Carnegie scientists and ongoing collaborators Ho-Kwang “Dave” Mao and Qingyang Hu of the Center for High Pressure Science and Technology Advanced Research Shanghai and Yue Meng of Argonne National Laboratory—demonstrates that a key

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The Geophysical Laboratory has made important advances in the growth of diamond by chemical vapor deposition (CVD).  Methods have been developed to produce single-crystal diamond at low pressure having a broad range of properties.

Johanna Teske became the first new staff member to join Carnegie’s newly named Earth and Planets Laboratory (EPL) in Washington, D.C., on September 1, 2020. She has been a NASA Hubble Fellow at the Carnegie Observatories in Pasadena, CA, since 2018. From 2014 to 2017 she was the Carnegie Origins Postdoctoral Fellow—a joint position between Carnegie’s Department of Terrestrial Magnetism (now part of EPL) and the Carnegie Observatories.

Teske is interested in the diversity in exoplanet compositions and the origins of that diversity. She uses observations to estimate exoplanet interior and atmospheric compositions, and the chemical environments of their formation

Phillip Cleves’ Ph.D. research was on determining the genetic changes that drive morphological evolution. He used the emerging model organism, the stickleback fish, to map genetic changes that control skeletal evolution. Using new genetic mapping and reverse genetic tools developed during his Ph.D., Cleves identified regulatory changes in a protein called bone morphogenetic protein 6 that were responsible for an evolved increase in tooth number in stickleback. This work illustrated how molecular changes can generate morphological novelty in vertebrates.

Cleves returned to his passion for coral research in his postdoctoral work in John Pringles’ lab at Stanford

Brittany Belin joined the Department of Embryology staff in August 2020. Her Ph.D. research involved developing new tools for in vivo imaging of actin in cell nuclei. Actin is a major structural element in eukaryotic cells—cells with a nucleus and organelles —forming contractile polymers that drive muscle contraction, the migration of immune cells to  infection sites, and the movement of signals from one part of a cell to another. Using the tools developed in her Ph.D., Belin discovered a new role for actin in aiding the repair of DNA breaks in human cells caused by carcinogens, UV light, and other mutagens.

Belin changed course for her postdoctoral work, in

Evolutionary geneticist Moises Exposito-Alonso joined the Department of Plant Biology as a staff associate in September 2019. He investigates whether and how plants will evolve to keep pace with climate change by conducting large-scale ecological and genome sequencing experiments. He also develops computational methods to derive fundamental principles of evolution, such as how fast natural populations acquire new mutations and how past climates shaped continental-scale biodiversity patterns. His goal is to use these first principles and computational approaches to forecast evolutionary outcomes of populations under climate change to anticipate potential future