The Walsh Lab synthesizes solid-state compounds at pressures up to millions of atmospheres, reaching phases of matter that don't exist on Earth's surface.
We are a materials chemistry group studying new synthesis routes under extreme compression. We use experimental techniques to subject samples to pressures on the order of millions of atmospheres, allowing us to access exotic states of matter and synthesize undiscovered solid-state compounds. We also use first-principles calculations to explore high-pressure phase space in silico, and to study the bulk properties of newly discovered phases.
High pressure represents a vastly unexplored phase space where new compounds can be synthesized and recovered back to ambient conditions. We use experimental high-pressure synthesis techniques to discover completely new solid-state compounds.
Predicting which compounds form at extreme pressure is a vast computational problem. We use random structure searching tools to perform high-throughput DFT calculations in search of undiscovered high-pressure phases. We also use machine learning methods to investigate how pressure can influence chemical disorder in the solid state.
Systems that exhibit magnetic frustration are a direct route to exotic new states of matter dominated by quantum fluctuations. Control over these delicate quantum states is an outstanding challenge in chemistry and physics. We are using high pressures to target novel quantum phases in geometrically frustrated systems.
Phase space, technically.
The Walsh Lab shortly before braving the snow for group dinner.
walshlab@mainframe:~$ ./mission status stardate — | current location 42.3936°N 72.5267°W walshlab@mainframe:~$ ./mission manifest --cards retrieving records | rendering...
walshlab@mainframe:~$ ./mission manifest --alumni --cards retrieving records | rendering...
High-pressure synthesis of a novel body-centered tetragonal vanadium carbide
Cote, E. E.; Nelson, T. L.; Ambos, S. D.; Arigbede, J.; Walsh, C.; Bernard, R. E.; Brooks H. L.; Whitaker, M. L.; Walsh, J. P. S.
Chem. - Eur. J. 2026, e202502753. PDF
Stability of the fcc phase in shocked nickel up to 332 GPa
Pereira, K. A.; Clarke, S. M.; Singh, S; Briggs, R.; McGuire, C. P.; Lee, H. J.; Khaghani, D.; Nagler, B.; Galtier, E.; Cunningham, E.; McGonegle, D.; Tracy, S. J.; Vennari, C.; Gorman, M. G.; Coleman, A. L.; Davis, C.; Hutchinson, T.; Eggert, J. H.; Smith, R. F.; Walsh, J. P. S.
Nat. Commun. 2025, 16, 4385. PDF
Fragmenting the kagomé lattice: Pressure-tuned anisotropy of Cu2+ triangles in a novel atacamite relative, CaCu(OH)3Cl
Ambos, S. D.; Manganaro, N. S.; DeCapua, M.; Zhang, D.; Nguyen, P.; Yan, J.; Walsh, J. P. S.
J. Phys. Chem. C 2024, 129, 4226–4232. PDF Front Cover
High-pressure synthesis and recovery of single crystals of the metastable manganese carbide, MnCx
Marshall, P. V.; Thiel, S. D.; Cote, E. E.; Arigbede, J.; Whitaker, M. L.; Walsh, J. P. S.
Chem. - Eur. J. 2024, 30, e202401581. PDF
High-pressure polymorphism in silver ferrite delafossite, AgFeO2
Manganaro, N. S.; Ambos, S. D.; DeCapua, M.; Thiel S. D., Mitchell, W. E.; Liu, Z.; Zhang, D.; Nguyen, P. Q. H.; Lavina, B.; Alp, E. E.; Yan, J.; Walsh, J. P. S.
Inorg. Chem. 2024, 63, 9763–9770. PDF
Combined first-principles and experimental investigation into the reactivity of co-deposited chromium–carbon samples under pressure
Marshall, P. V.; Thiel, S. D.; Cote, E. E.; Hrubiak, R.; Whitaker, M. L.; Meng, Y.; Walsh, J. P. S.
ACS Mater. Au 2024, 63, 9763–9770. PDF Front Cover
First-principles investigation of phase stability in substoichiometric zirconium carbide under high pressure
Thiel, S. D.; Walsh, J. P. S.
Adv. Theory Simul. 2022, 5, 2200439. PDF Front Cover
X-ray diffraction methods for high-pressure solid-state synthesis (Book Chapter)
Thiel, S. D.; Tamerius, A. D.; Walsh, J. P. S.
Compr. Inorg. Chem. III 2022, 200–221.
High-pressure synthesis of bulk cobalt cementite, Co3C
Marshall, P. V.; Alptekin, Z.; Thiel, S. D.; Smith, D.; Meng, Y.; Walsh, J. P. S.
Chem. Mater. 2021, 33, 9601–9607. PDF Front Cover
High-pressure chemistry
Walsh, J. P. S.
Commun. Chem., 2025, 8, 168 PDF
Shock compression experiments using the DiPOLE 100-X laser on the high energy density instrument at the European X-ray free electron laser: Quantitative structural analysis of liquid Sn
Gorman, M. G.; [...] Pereira, K. A.; [...] Walsh, J. P. S.; [...] McMahon, M. I.
J. Appl. Phys., 2024, 135, 165902 PDF
Designing magnetic properties in CrSBr through hydrostatic pressure and ligand substitution
Telford, E. J.; Chica, D. G.; Ziebel, M. E.; Xie, K; Manganaro, N. S.; Huang, C.-Y.; Cox, J.; Dismukes, A. H.; Zhu, X.; Walsh, J. P. S.; Cao, T.; Dean, C. R.; Roy X.
Adv. Physics Res., 2023, 2, 2300036. PDF
"Pink"-beam X-ray powder diffraction profile and its use in Rietveld refinement
Von Dreele, R.; Clarke S. M.; Walsh, J. P. S.
J. Appl. Cryst., 2021, 54, 3–6. PDF
Anisotropic structural collapse of Mg3Sb2 and Mg3Bi2 at high pressure
Calderón-Cueva, M.; Peng, W.; Clarke S. M.; Ding, J.; Brugman, B. L.; Levental, G.; Balodhi, A.; Rylko, M.; Delaire, O.; Walsh, J. P. S.; Dorfman, S. M.; Zevalkink, A.
Chem. Mater., 2021, 33, 567–573. PDF
Computationally directed discovery of MoBi2
Altman, A. B.; Tamerius, A. D.; Koocher, N. Z.; Meng, Y.; Pickard, C.; Walsh, J. P. S.; Rondinelli, J. M.; Jacobsen, S. D.; Freedman, D. E.
J. Am. Chem. Soc. 2021, 143, 214–222. PDF
Pressure induced collapse of magnetic order in jarosite
Klein, R. A.; Walsh, J. P. S.; Clarke S. M.; Liu, Z.; Alp, E. E.; Bi, W.; Meng, Y.; Altman, A. B.; Chow, P.; Xiao, Y.; Norman, M. R.; Rondinelli, J. M.; Jacobsen, S. D.; Puggioni, D.; Freedman, D. E.
Phys. Rev. Lett. 2020, 125, 077202. PDF
High-pressure synthesis of the BiVO3 perovskite
Klein, R. A.; Altman, A. B.; Saballos, R. J.; Walsh, J. P. S.; Tamerius, A. D.; Meng, Y.; Puggioni, D.; Jacobsen, S. D.; Rondinelli, J. M.; Freedman, D. E.
Phys. Rev. Mater. 2019, 3, 64411. PDF
MnBi2: A metastable high-pressure phase in the Mn–Bi system
Walsh, J. P. S.; Clarke S. M.; Puggioni, D.; Tamerius, A. D.; Meng, Y.; Rondinelli, J. M.; Jacobsen, S. D.; Freedman, D. E.
Chem. Mater. 2019, 31, 3083–3088. PDF
Controlling dimensionality in the Ni–Bi system with pressure
Clarke S. M.; Powderly, K. M.; Walsh, J. P. S.; Yu, T.; Wang, Y.; Meng; Y.; Jacobsen, S. D.; Freedman, D. E.
Chem. Mater. 2019, 31, 955–959. PDF
Discovery of Cu3Pb
Tamerius, A. D.; Clarke S. M.; Gu, M.; Walsh, J. P. S.; Esters, M.; Meng, Y.; Hendon, C. H.; Rondinelli, J. M.; Jacobsen, S. D.; Freedman, D. E.
Angew. Chem. Int. Ed. 2018, 57, 12809–12813. PDF
Impact of pressure on magnetic order in jarosite
Klein, R. A.; Walsh, J. P. S; Clarke S. M.; Guo, Y.; Bi, W.; Fabbris, G.; Meng, Y.; Haskel, D.; Alp, E. E.; Van Duyne, R. P.; Jacobsen, S. D.; Freedman, D. E.
J. Am. Chem. Soc. 2018, 140, 12001–12009. PDF Front Cover
High-pressure synthesis: A new frontier in the search for next-generation intermetallic compounds
Walsh, J. P. S.; Freedman, D. E.
Acc. Chem. Res. 2018, 51, 1315–1323. PDF
Creating binary Cu–Bi compounds via high-pressure synthesis: A combined experimental and theoretical study
Clarke S. M.; Amsler, M.; Walsh, J. P. S.; Yu, T.; Wang, Y.; Meng, Y.; Jacobsen, S. D.; Wolverton, C.; Freedman, D. E.
Chem. Mater. 2017, 29, 5276–5285. PDF
Discovery of FeBi2
Walsh, J. P. S.; Clarke S. M.; Meng, Y.; Jacobsen, S. D.; Freedman, D. E.
ACS Cent. Sci. 2016, 2, 867–871. PDF
Discovery of a superconducting Cu–Bi intermetallic compound by high-pressure synthesis
Clarke, S. M.; Walsh, J. P. S.; Amsler, M.; Malliakas, C. D.; Yu, T.; Goedecker, S.; Wang, Y.; Wolverton, C.; Freedman, D. E.
Angew. Chem. Int. Ed. 2016, 55, 13446–13449. PDF
John has been honored with the UMass Amherst Graduate School's Commitment to Diversity Award, presented during the 2026 Doctoral Hooding Ceremony. The award recognizes outstanding contributions to diversity and inclusion within the graduate student body. Congratulations, John!
Liz has been awarded a PPG Fellowship in support of her graduate research. Congratulations, Liz!
Liz's paper on the high-pressure synthesis of a novel body-centered tetragonal vanadium carbide has been published in Chemistry – A European Journal. Congratulations, Liz!
Kaiden won a poster prize at the Harry C. Allen Jr. Symposium held at Clark University in Worcester! He presented on his work using data-derived potentials for large-scale crystal structure predictions. Great job, Kaiden!
Liz presented a poster on the high-pressure synthesis of transition metal carbides at the 2026 College of Natural Sciences Graduate Research Symposium. Great work, Liz!
Liz and James headed to the APS Global Physics Summit. James gave an invited talk in the Compression of Condensed Matter session, and Liz presented her vanadium carbide work in High Pressure Structure I. A photo op with Schrödinger's cat was, of course, mandatory.
John presented his research at the inaugural UMass Engineering Research Symposium, hosted by the Department of Chemical Engineering. Great work, John!
Liz brought Anshu on her first trip to the large volume press at NSLS-II Sector 28-ID-B for high-pressure synthesis of transition metal carbides. Thank you to Matt Whitaker for making Anshu's first beamtime a success!
Look who Liz and Tracey ran into at the APS — Dr. Scott Ambos! Now a postdoc on the HPCAT team, Scott helped his old labmates push through their experiments. Don't worry, plenty of work got done in between catching up.
Tracey and Liz return to APS Sector 16-ID-B for laser-heated diamond anvil cell experiments! Thank you to Ross Hrubiak for assisting with Tracey and Liz's latest visit to the APS — a successful end to a busy 2025 of beamtimes!
Scott successfully defended his Ph.D. thesis, "Crystallographic Methods at High Pressure." He is now a postdoc with the HPCAT team at the Advanced Photon Source. Congratulations, Scott!
The dynamic duo returns for more experiments at Sector 28-ID-D. Thank you to Matt Whitaker for his support in these experiments!
Liz and James headed to Brookhaven National Lab for the PDC 2025. Liz gave an oral presentation at the In-Situ Methods at High Pressure session and participated as a panelist in the Early Career Panel Discussion. Congratulations to Liz on winning the inaugural Sharkington-Harris Emerging Scientist Award for her excellent talk!
We are thrilled to welcome Changjiang Wu to the Walsh Lab! Changjiang graduated from Renmin University in Beijing, China, and joins us through the MSE IDGP. He will work on the development and implementation of new crystal structure prediction methods.
The High-Pressure Synthesis team was back at HPCAT for LH-DAC synthesis development using our co-sputtered samples.
We carried out some inter-state laser heating with help from the Hemley Group at UIC.
James authored an editorial titled High-pressure chemistry introducing a Collection of articles spanning the breadth of the field. Read it here.
Kim's collaborative work studying the stability of the fcc phase in shocked nickel up to 332 GPa has been published in Nature Communications. Congratulations, Kim!
Anshu, Tracey, and Liz attended the inaugural NESACS (Northeastern Section of the American Chemical Society) Celebrating Women's Careers in Chemistry. This event allowed them to present their research and network with women in the field.
Anshu Baiya has joined the Walsh Lab as a graduate student, and we couldn't be more excited to have her on board! Anshu earned her chemistry degree at the Indian Institute of Technology Varanasi, and will help drive forward our experimental high-pressure materials discovery program.
Scott's paper on the pressure-tuned anisotropy of Cu2+ triangles in the atacamite relative CaCu(OH)3Cl has been published in J. Phys. Chem. C, and was selected for a front cover. Congratulations, Scott!
Liz and Tracey return to the NSLS-II for more multi-anvil press experiments. Tracey helped to improve the beamline operations and experimental team morale.
Liz and Tracey were able to successfully complete DAC experiments with the newly updated beam at Beamline 16-ID-B! Thank you to Ross Hrubiak and Dean Smith for their assistance during Tracey and Liz's first visit to the APS!
Liz Cote and Tracey Nelson each won poster prizes at ResearchFest 2024. Liz won the Marvin D. Rausch Lectureship Award for Outstanding Poster Presentation while Tracey won the Dr. Paul Hatheway Terry Endowment Award for Outstanding Poster.
Kim successfully defended her Ph.D. thesis, "Exploring the phase transitions of materials using femtosecond X-ray diffraction under dynamic compression." She will join Coherent Corp. as a Senior Laser Product Engineer. Congratulations, Kim!
Nick successfully defended his Ph.D. thesis, "Polymorphism in Silver Delafossites Under Extreme Pressures." He will join Bates College as a lecturer in the chemistry department this fall. Congratulations, Nick!
Scott successfully defended his Ph.D. thesis, "On the Non-Stoichiometry and Phase Stability of Transition Metal Carbides Under High Pressures." He will join Stefano Curtarolo's group at Duke as a postdoc this fall. Congratulations, Scott!
Paul successfully defended his Ph.D. thesis, "Materials Discovery at Extreme Conditions." He will join Alison Altman's group at Texas A&M as a postdoc this fall. Congratulations, Paul!
Liz and Tracey ran their first laser-heated DAC experiment at the 12.2.2 beamline at the Advanced Light Source in Berkeley, CA. Thank you to Kat Armstrong for helping us navigate our first beamtime at the ALS!
Paul's paper on the high-pressure synthesis and recovery of single crystals of metastable manganese carbide, MnCx, has been published in Chemistry – A European Journal. Congratulations, Paul!
Nick's paper on high-pressure polymorphism in silver ferrite delafossite, AgFeO2, has been published in Inorganic Chemistry. Great work, Nick!
Zeynep Alptekin has accepted an offer to join the materials science and engineering graduate program at Northwestern University, starting in Fall 2024. Congratulations, Zeynep!
Wyatt Mitchell has accepted an offer to join the chemistry graduate program at Michigan State University, starting in Fall 2024. Congratulations, Wyatt! And Go Green!
John Arigbede, Liz Cote, and Tracey Nelson visited the large volume press at the NSLS-II 28-ID-2 beamline to carry out more high-pressure syntheses of transition metal carbides. Thank you to Matt Whitaker for making John and Tracey's first visit a success!
We are delighted to welcome Tracey Nelson to the Walsh Lab as a graduate student! Tracey earned her chemistry degree at St. Olaf College in Minnesota, where she worked in the lab of Prof. Elodie Marlier on new catalysts based on tetradentate N2P2 ligands.
Paul's combined first-principles and experimental investigation into the reactivity of co-deposited chromium–carbon under pressure has been published in ACS Materials Au, and was selected for a front cover. Congratulations, Paul!
Kim performed shockwave experiments across two systems on the Matter in Extreme Conditions Instrument at the LCLS in the SLAC National Accelerator Laboratory in California.
Nick Manganaro has started teaching his First Year Seminar course on game theory. This is a course that Nick designed from scratch as part of his CNS Teaching Fellowship. Good luck, Nick!
The Directed Energy Professional Society has awarded Kim a $10,000 research grant to support her collaborative work with LLNL on laser shock compression. Congratulations, Kim!
Work performed in collaboration with the Roy Research Group studying CrSBr under pressure was published in Advanced Physics Research. Check it out here!
James visited Lawrence Livermore National Laboratory in California to deliver a seminar in the Materials Science Division. While there, he caught up with Kim and Zeynep, who are both interning at the lab over the summer and doing great science!
Congratulations to John Arigbede, who has passed his ChemE qualifying exam and joined the Walsh Lab as a PhD candidate! John will study our newly discovered electron-rich transition metal carbides as heterogeneous catalysts.
The Walsh Lab has been awarded a grant from the American Chemical Society Petroleum Research Fund to study our novel transition metal carbides as heterogeneous catalysts!
The Walsh Lab was well represented at the Chemistry Department Awards Dinner, with Wyatt receiving the John A. Chandler Memorial Scholarship and Zeynep taking home the ACS Division of Inorganic Chemistry Undergraduate Award.
Liz Cote, Scott Thiel, and Paul Marshall carried out some high-pressure synthesis reactions on the large volume press at beamline 28-ID-2 at the NSLS-II.
Scott Ambos and Nick Manganaro were back at the APS to collect some high-pressure single crystal diffraction data. Thank you as always to Dongzhou Zhang and Phuong Nguyen for their support.
Kim will be spending the summer as a High Energy Density Science Center (HEDS) Grad Student at Lawrence Livermore National Laboratory.
The DOE Science Undergraduate Laboratory Internships (SULI) program will support Zeynep for a summer internship at Lawrence Livermore National Laboratory.
Nick Manganaro and Scott Ambos spent four days collecting high-pressure synchrotron Mössbauer at Sector 3 of the APS. Thank you to Barbara Lavina and Ercan Alp for helping us collect some great data!
We are happy to welcome Liz Cote to the Walsh Lab as a graduate student! Liz comes to us from the University of New Haven, where she worked with Prof. Dequan Xiao on the design of molecular catalysts for polymer degradations.
The Walsh Lab has been awarded an NSF CAREER grant to fund our work on the development of novel methods for high-pressure synthesis! We are very grateful to the Division of Materials Research for their support.
Kim was the recipient of not one but two chemistry graduate fellowships awarded through the department. She received both the Donald Kuhn Graduate Fellowship Award and the PPG Fellowship.
Paul Marshall and Scott Thiel set sail for Long Island to perform large volume press synthesis experiments at beamline 28-ID-2 of the NSLS-II.
Nick Manganaro and Scott Ambos visited the Partnership for Extreme Crystallography beamline at the APS to perform high-pressure X-ray crystallography experiments.
Kim won a first-place award for her poster presentation at the UMass Chemistry Department's ResearchFest 2022.
Scott's paper reporting on the use of cluster expansion to study the effect of pressure on vacancies in zirconium carbide has been published in Advanced Theory and Simulations. Great work, Scott!
Kim was back at the Advanced Photon Source to perform experiments at the Dynamic Compression Sector.
Kim won an award for her poster presentation of her shockwave work at the 2022 Research at High Pressure GRC. Her prize was a copy of Sergei Stishov's book The ABCs of High Pressure.
Wyatt was awarded the Roger G. Bates Fund to support his research in our lab over the summer.
Kim Bolduc, Nick Manganaro, and Scott Thiel each won the Chemistry Department Ambassador Award!
Zeynep was awarded the 2021–2022 UMass Rising Researcher Award for her outstanding achievements in research! Click here to read more. Congratulations, Zeynep!
Zeynep was awarded the Uche Anyanwu Memorial Award for her poster presentation at the Chemistry Undergraduate Poster Session.
Zeynep was awarded the prestigious Barry Goldwater Scholarship — one of only three students from UMass to receive the honor. Congratulations, Zeynep!
Kim led the Walsh Lab's first laser shock GUP beamtime at the Dynamic Compression Sector at the Advanced Photon Source, collecting our first in situ XRD and VISAR dataset!
Paul's paper reporting the high-pressure bulk synthesis of cobalt cementite in the laser-heated diamond anvil cell has been published in Chemistry of Materials. Great work, Paul!
Kim was awarded an Honorable Mention in this year's NSF GRFP — one of only two in the department. Congratulations, Kim!
Kim joined our awesome collaborators at Lawrence Livermore National Laboratory to perform experiments (remotely) on the Matter in Extreme Conditions endstation at SLAC National Accelerator Laboratory.
A warm welcome to Scott Ambos, who has officially joined the Walsh Lab as a graduate student! Scott comes to us from Union College, where he worked with Prof. Michael Hagerman on functionalized CdSe quantum dots for water-processable, inkjet-printed photovoltaics.
Kim virtually attended the UXSS held by Stanford University. Thank you to the organizers for a great workshop!
Our Rigaku Synergy-S single crystal diffractometer was delivered and commissioned in the basement of LGRT. It has a Cu/Ag dual source and is fitted with the HyPix-6000HE hybrid photon counting detector.
We spent two days meeting and catching up with other researchers in the high-pressure field at the annual HPCAT Conference held at the Advanced Photon Source.
Welcome to the first graduate students to join the Walsh Lab: Kimberly Bolduc, Nicholas Manganaro, Paul Marshall, and Scott Thiel. We are excited to get started!
