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DOE OSTI2026

Pressure-Stabilized MnSb2 with Complex Incommensurate Magnetic Order

Marcasite-type compounds have been proposed as promising hosts of exotic magnetic quantum states, yet experimental realizations in stoichiometric, disorder-free systems remain limited. Here, we report the high-pressure stabilization and magnetic characterization of MnSb2, a marcasite-type compound that is thermodynamically metastable under ambient pressure. Single crystals were synthesized using a cubic multianvil press at 3.3 GPa and 490 °C for 24 h, and powder and single-crystal X-ray diffraction confirm the orthorhombic Pnnm structure. These crystals are stable at ambient pressure for a long time up to between 450 and 500 K. Heat-capacity measurements reveal phase transitions at approximately T0 ∼ 118 K and T1 ∼ 220 K. Neutron diffraction uncovers an unconventional magnetic state below T1 ∼ 220 K. Magnetic powder neutron diffraction refinements reveal possible multiple magnetic configurations that provide comparably acceptable fits to the experimental data. While most solutions are consistent with a spin-density-wave (SDW) description, helical models systematically yield inferior agreement factors. Across a broad range of models, the Mn ordered moment reaches a maximum value of approximately 2 μB and remains predominantly collinear, with minimal canting along the c-axis. At 200 K, the magnetic propagation vector is q = (0, 0.3975, 0.3783); upon cooling, the b component increases toward 0.5, reflecting a temperature-dependent evolution of the modulation. The need for modification of the magnetic model between high and low temperatures further highlights the complex and strongly temperature-dependent nature of the magnetic order in this system. These results establish MnSb2 as a pressure-stabilized marcasite magnet with a tunable, complex magnetic state and a compelling stoichiometric platform for exploring unconventional magnetic behavior, including potential altermagnetism.

Xu, Mingyu [Michigan State University , , , ,; Iow↗

DOE OSTI2016

Multi-Pack Disposal Concepts for Spent Fuel (Revision 1)

At the initiation of the Used Fuel Disposition (UFD) R&D campaign, international geologic disposal programs and past work in the U.S. were surveyed to identify viable disposal concepts for crystalline, clay/shale, and salt host media. Concepts for disposal of commercial spent nuclear fuel (SNF) and high-level waste (HLW) from reprocessing are relatively advanced in countries such as Finland, France, and Sweden. The UFD work quickly showed that these international concepts are all “enclosed,” whereby waste packages are emplaced in direct or close contact with natural or engineered materials . Alternative “open” modes (emplacement tunnels are kept open after emplacement for extended ventilation) have been limited to the Yucca Mountain License Application Design. Thermal analysis showed that if “enclosed” concepts are constrained by peak package/buffer temperature, that waste package capacity is limited to 4 PWR assemblies (or 9 BWR) in all media except salt. This information motivated separate studies: 1) extend the peak temperature tolerance of backfill materials, which is ongoing; and 2) develop small canisters (up to 4-PWR size) that can be grouped in larger multi-pack units for convenience of storage, transportation, and possibly disposal (should the disposal concept permit larger packages). A recent result from the second line of investigation is the Task Order 18 report: Generic Design for Small Standardized Transportation, Aging and Disposal Canister Systems. This report identifies disposal concepts for the small canisters (4-PWR size) drawing heavily on previous work, and for the multi-pack (16-PWR or 36-BWR).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

The energetics and dynamics of confinement in flexible frameworks and molecular confinement

This project is part of an ongoing and long-term collaboration among Alexandra Navrotsky (who moved recently from UC Davis to Arizona State University), Nancy Ross at Virginia Tech, and Brian Woodfield at Brigham Young University (BYU) on the thermodynamics and lattice dynamics of nanophase and porous materials. Navrotsky emphasizes energetics of formation and guest molecule sorption by ambient and high temperature calorimetry, Woodfield contributes cryogenic heat capacity measurements, and Ross uses inelastic neutron scattering, X-ray and neutron diffraction, and high pressure studies to probe lattice dynamics and phase transitions. Porous frameworks form the chemical and structural basis for critical technologies in separations, catalysis, nuclear waste containment and biomedical applications. Hundreds of zeolites and metal organic frameworks (MOFs) have been synthesized, and their ability to separate and store hydrogen, methane and carbon dioxide has been investigated both experimentally and theoretically. Nevertheless, a fundamental and systematic molecular-level understanding of the thermodynamic and structural factors governing the stability and guest-host interactions in these materials lags behind focused studies of specific systems. Because the guest molecules interact with each other and with the host framework, molecular confinement is a finely balanced and complex phenomenon. The ability of the guest molecules to bind and diffuse through the pores is determined by the nature of the host framework which, in turn, responds to the nature and concentration of guest molecules and to pressure and temperature. The work explores how framework flexibility, tailored by structure, composition, temperature and pressure, is a general phenomenon, similar in nature but variable in extent, in both zeolites and MOFs and is part of a free energy landscape in which framework-guest interactions, pressure, and temperature result in changes in framework geometry and, in some cases, phase transitions. These subtle and/or pronounced changes in lattice geometry, energetics, and dynamics can play a decisive role in confinement and in differentiating the binding of molecules of similar size.

36 MATERIALS SCIENCE↗

DOE OSTI2015

Favorable tectonic and structural settings of geothermal systems in the Great Basin region, western USA: Proxies for discovering blind geothermal systems

We recently completed a comprehensive inventory of the structural settings of known geothermal systems (426 total, ≥37°C) in the extensional to transtensional terrane of the Great Basin region in the western USA. Of the known systems, ~39% are blind (no surface hot springs or fumaroles), but estimates suggest that as much as 75% of the geothermal resources in the region are blind. The density of geothermal systems and capacity of power plants correlate generally with tectonic strain rates. However, highenthalpy geothermal activity is restricted to regions of extensional to transtensional strain, particularly the northwestern part of the Great Basin directly northeast of the dextral shear zone of the Walker Lane and pull-apart zones within both the Walker Lane and San Andreas fault system. We catalogued systems into eight major groups, based on the dominant pattern of faulting. Of the nearly 250 categorized geothermal fields, we found that step-overs or relay ramps in normal fault zones are the most favorable setting, hosting ~32% of the systems. Such areas are characterized by multiple, commonly overlapping fault strands, increased fracture density, and thus enhanced permeability. Other common settings include a) normal fault terminations (25%), where horse-tailing generates a myriad of closely-spaced faults and thus increased permeability; and b) fault intersections between two normal faults or between normal faults and transverse oblique-slip faults (22%), where multiple minor faults typically connect major structures and fluids can flow readily through highly fractured, dilational quadrants. Less common settings include: a) accommodation zones (9%); b) displacement transfer zones (5%); c) pull-aparts in strike-slip faults (3%); d) bends in normal faults (2%); and e) major range-front normal faults (1%). Pull-aparts and displacement transfer zones are more abundant in the transtensional western part of the Great Basin. Quaternary faults typically lie within or near most of the geothermal systems. Geothermal systems are rare along major range-front faults, possibly due to both reduced permeability in thick zones of clay gouge and periodic release of stress in major earthquakes. Step-overs, terminations, intersections, and accommodation zones correspond to long-term, critically stressed areas, where fluid pathways would more likely remain open in networks of closely-spaced, breccia-dominated fractures. Notably, many higher enthalpy systems are hybrids and contain more than one type of favorable setting (e.g. fault intersection within broad accommodation zone). These data can guide exploration strategies, especially for blind or hidden systems.

15 GEOTHERMAL ENERGY↗

DOE OSTI2016

Neutron diffraction analysis and electrochemical performance of spinel Ni(Mn{sub 2−x}Co{sub x})O{sub 4} as anode materials for lithium ion battery

Highlights: • The reversible capacity and cyclability of Ni(Mn{sub 2−x}Co{sub x})O{sub 4} first increases and then decreases with increasing Co content. • Neutron diffraction and Rielveld refinements are applied to analyze the site occupancies of Mn, Co, O and Ni. • Excessive Co ions in 8a and 16d sites reduce the structure stability leading to poor electrochemical performance. - Abstract: The effects of Co substitution on the structure and electrochemical performances of spinel Ni(Mn{sub 2−x}Co{sub x})O{sub 4} (x = 0, 0.5, and 1.0) have been investigated. With the increase of Co content the lattice parameters decrease owing to the smaller ion radius of Co than Mn. The reversible capacity and cyclability of Ni(Mn{sub 2−x}Co{sub x})O{sub 4} first increase and then decrease with the increase of Co content and NiMn{sub 1.5}Co{sub 0.5}O{sub 4} shows the best electrochemical performance in compared to the other two samples. Neutron diffraction and Rielveld refinement are further applied to analyze the site occupancies of the elements of Mn, Co, O and Ni. A certain amount of Co ions substitution are favorable to enhance the electrochemical performance, but excessive Co ions in 8a and 16d sites reduce the stability of host structure which leads to the poor electrochemical performance.

36 MATERIALS SCIENCE↗

DOE OSTI2018

Zeolite-like MOF nanocrystals incorporated 6FDA-polyimide mixed-matrix membranes for CO 2 /CH 4 separation

MOF mixed-matrix membranes (MMMs) are regarded as potential candidates for energy-efficient natural gas purification. Our work reports the fabrication of high-performance 6FDA-polyimide MMMs, based on the incorporation of zeolite-like MOF (ZMOF) as fillers, and their associated permeation studies for CO 2 /CH 4 separation. To eliminate micron-sized crystals, a facile repeating sedimentation approach was used to harvest nanocrystals from the as-synthesized bulk ZMOF crystalline powder material. This enables the deployment of ZMOF nanocrystals with relatively uniform dimension and morphology in the polymer matrix. Typical 6FDA-polyimides encompassing distinct diamine moieties (6FDA-DAM, 6FDA-DETDA-DABA or PDMC) were explored as polymer matrices to disclose the transport property matching the hosted ZMOF filler. Mixed-gas permeation measurements revealed that the incorporation of the ZMOF filler affords a concurrent enhancement of the CO 2 permeability and the CO 2 /CH 4 selectivity for the three tested 6FDA-polyimides. Particularly, the highly permeable 6FDA-DAM showed a considerably enhanced performance for CO 2 /CH 4 that transcends the 2008 Robeson upper-bound. Detailed analysis of the sorption data and diffusion coefficients suggest that the enhanced transport property in the ZMOF-based MMM is plausibly attributed to the combination of the higher CO 2 sorption capacity and selectivity, and favorable gas diffusivity via the CO 2 -philic framework of ZMOF in moderately confined pores.

36 MATERIALS SCIENCE↗

DOE OSTI2018

Control of thermal expansion in a low-density framework modification of silicon

The low-density clathrate-II modification of silicon, Si 136 , contains two distinct cage-like voids large enough to accommodate various types of guest atoms which influence both the host structure and its properties. Although the linear coefficient of thermal expansion of Si 136 (293 K < T < 423 K) is only about 20% larger than that of the ground state α-Si (diamond structure), the coefficient of thermal expansion monotonically increases by more than 150% upon filling the framework cages with Na atoms in Na x Si 136 (0 < x < 24), ranging from α = 2.6 x 10 –6 K –1 (x = 0) to 6.8 × 10 –6 K –1 (extrapolated to x = 24) by only varying the Na content, x. Taken together with the available heat capacity and bulk modulus data, the dramatic increase in thermal expansion can be attributed to an increase in the mode-averaged Grüneisen parameter by a factor of nearly 3 from x = 0 to x = 24. Furthermore, these results highlight a potential mechanism for tuning thermal expansion, whereby guest atoms are incorporated into the voids of rigid, covalently bonded inorganic frameworks to influence the lattice dynamics.

36 MATERIALS SCIENCE↗

NASA NTRS1993

Evolution of a high-performance storage system based on magnetic tape instrumentation recorders

In order to provide transparent access to data in network computing environments, high performance storage systems are getting smarter as well as faster. Magnetic tape instrumentation recorders contain an increasing amount of intelligence in the form of software and firmware that manages the processes of capturing input signals and data, putting them on media and then reproducing or playing them back. Such intelligence makes them better recorders, ideally suited for applications requiring the high-speed capture and playback of large streams of signals or data. In order to make recorders better storage systems, intelligence is also being added to provide appropriate computer and network interfaces along with services that enable them to interoperate with host computers or network client and server entities. Thus, recorders are evolving into high-performance storage systems that become an integral part of a shared information system. Data tape has embarked on a program with the Caltech sponsored Concurrent Supercomputer Consortium to develop a smart mass storage system. Working within the framework of the emerging IEEE Mass Storage System Reference Model, a high-performance storage system that works with the STX File Server to provide storage services for the Intel Touchstone Delta Supercomputer is being built. Our objective is to provide the required high storage capacity and transfer rate to support grand challenge applications, such as global climate modeling.

Peters, Bruce↗

DOE OSTI2019

Ultradispersed W x C nanoparticles enable fast polysulfide interconversion for high-performance Li-S batteries

Li-S batteries are a promising next-generation battery technology but are confronted with a series of fundamental challenges, in particular the notorious shuttle effect of soluble polysulfide intermediates. Current research efforts are mostly focused on designing proper host materials for the entrapment and immobilization of polysulfides. Herein, we demonstrate that electrocatalysis may play an unexpected role in Li-S batteries. Nanosized tungsten carbide particles dispersed on the carbonaceous support are prepared from the pyrolysis of phosphotungstic acid-functionalized metal-organic frameworks. Both experimental measurements and theoretical calculations demonstrate that they not only have strong affinity toward polysulfide intermediates, but also significantly accelerate the reduction of low-order polysulfides that is otherwise kinetically challenged. Furthermore, using these supported tungsten carbide nanoparticles as the cathode catalyst, our Li-S batteries achieve large capacity, excellent cycling stability and impressive rate capability.

25 ENERGY STORAGE↗

DOE OSTI2012

Status and trends in networking at LHC Tier1 facilities

The LHC is entering its fourth year of production operation. Most Tier1 facilities have been in operation for almost a decade, when development and ramp-up efforts are included. LHC's distributed computing model is based on the availability of high capacity, high performance network facilities for both the WAN and LAN data movement, particularly within the Tier1 centers. As a result, the Tier1 centers tend to be on the leading edge of data center networking technology. In this paper, we analyze past and current developments in Tier1 LAN networking, as well as extrapolating where we anticipate networking technology is heading. Our analysis will include examination into the following areas: Evolution of Tier1 centers to their current state Evolving data center networking models and how they apply to Tier1 centers Impact of emerging network technologies (e.g. 10GE-connected hosts, 40GE/100GE links, IPv6) on Tier1 centers Trends in WAN data movement and emergence of software-defined WAN network capabilities Network virtualization

Bobyshev, A.↗

DOE OSTI2021

A CRISPR-Cas9–integrase complex generates precise DNA fragments for genome integration

CRISPR-Cas9 is an RNA-guided DNA endonuclease involved in bacterial adaptive immunity and widely repurposed for genome editing in human cells, animals and plants. In bacteria, RNA molecules that guide Cas9 s activity derive from foreign DNA fragments that are captured and integrated into the host CRISPR genomic locus by the Cas1-Cas2 CRISPR integrase. How cells generate the specific lengths of DNA required for integrase capture is a central unanswered question of type II-A CRISPR-based adaptive immunity. Here, we show that an integrase supercomplex comprising guide RNA and the proteins Cas1, Cas2, Csn2 and Cas9 generates precisely trimmed 30-base pair DNA molecules required for genome integration. The HNH active site of Cas9 catalyzes exonucleolytic DNA trimming by a mechanism that is independent of the guide RNA sequence. These results show that Cas9 possesses a distinct catalytic capacity for generating immunological memory in prokaryotes.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2025

Predicting Quantum Criticality in Single-Crystalline Ce 2 Ru 3 Ge 5

Strongly correlated f-electron systems are known to host exotic quantum states, such as quantum criticality, complex order parameters, and unconventional superconductivity. However, the appearance of these exotic states is difficult to predict, making the study of quantum critical behavior challenging, especially in ferromagnetic materials. Herein, we report a structure–property map for Ce 2 M 3 X 5 (M = transition metal; X = main group element) that aids in the targeted design of materials likely to exhibit quantum criticality. Guided by this map, we report on the synthesis of single-crystalline Ce 2 Ru 3 Ge 5 and provide, for the first time, magnetic susceptibility, heat capacity, resistivity, and magnetoresistance measurements on single crystals. Here, we observe a weak ferromagnetic-like response at 7.5 K, which is contrasted with the bulk ferromagnetic ordering that appears in polycrystalline samples. Non-Fermi liquid behavior is seen in the temperature dependent electrical resistivity and heat capacity of the single crystals, suggesting proximity to a ferromagnetic quantum critical point without chemical or physical pressure. Given the contrast with previous reports of polycrystals, these results lead us to propose that single crystalline Ce 2 Ru 3 Ge 5 is intrinsically tuned into the vicinity of a ferromagnetic quantum critical point.

36 MATERIALS SCIENCE↗

DOE OSTI2025

Magnetic dilution in the triangular lattice antiferromagnet NaYb 1−𝑥 ⁢Lu 𝑥 ⁢O 2

The delafossitelike compound NaYbO 2 hosts a triangular lattice of Yb 3+ moments and is a promising candidate for the realization of a quantum spin liquid ground state—an exotic, quantum-disordered magnetic phase featuring long-range entanglement of spins. Tuning this system away from this quantum-disordered regime toward classical order or spin freezing is a powerful approach to shed light on the nature of the parent ground state. Here we leverage the substitution of nonmagnetic Lu 3+ onto the Yb 3+ sites to study the effects of magnetic disorder in NaYbO 2 using low-temperature ac susceptibility, heat capacity, and muon spin relaxation (𝜇⁢SR) measurements. Here, our 𝜇⁢SR measurements reveal resilient, correlated magnetic fluctuations that persist to at least 15% dilution, precluding conventional spin freezing and magnetic inhomogeneity. Heat capacity and magnetic susceptibility resolve a rapid suppression of the field-induced “up-up-down” magnetic order upon dilution and a crossover in the power-law behavior of the low-temperature magnetic excitations associated with the zero-field quantum disordered ground state. Taken together, these results support the notion of a robust network of entangled moments in NaYbO 2 and provide experimental validation of several models of a Heisenberg triangular lattice antiferromagnet in the presence of disorder.

Muon spin relaxation & rotation↗

DOE OSTI2015

Final Report: "Energetics of Nanomaterials

Nanomaterials, solids with very small particle size, form the basis of new technologies that are revolutionizing fields such as energy, lighting, electronics, medical diagnostics, and drug delivery. These nanoparticles are different from conventional bulk materials in many ways we do not yet fully understand. This project focused on their structure and thermodynamics and emphasized the role of water in nanoparticle surfaces. Using a unique and synergistic combination of high-tech techniques—namely oxide melt solution calorimetry, cryogenic heat capacity measurements, and inelastic neutron scattering—this work has identified differences in structure, thermodynamic stability, and water behavior on nanoparticles as a function of composition and particle size. The systematics obtained increase the fundamental understanding needed to synthesize, retain, and apply these technologically important nanomaterials and to predict and tailor new materials for enhanced functionality, eventually leading to a more sustainable way of life. Highlights are reported on the following topics: surface energies, thermochemistry of nanoparticles, and changes in stability at the nanoscale; heat capacity models and the gapped phonon spectrum; control of pore structure, acid sites, and thermal stability in synthetic γ-aluminas; the lattice contribution is the same for bulk and nanomaterials; and inelastic neutron scattering studies of water on nanoparticle surfaces.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2025

MSD CoP Webinar: Energy and AI

Context: This webinar was hosted by the MultiSector Dynamics Community of Practice (MSD CoP; https://multisectordynamics.org). Abstract: Projections of the need for new data centers to support Artificial Intelligence (AI) are large but highly uncertain. Recent projections indicate up to a 15% annual growth rate in data center electricity demand within the next 5-10 years. Given that most electric utilities are required to have a reserve margin of roughly the same magnitude as the projected growth in demand, these new data center loads could soon threaten resource adequacy and reliability unless data centers build their own generation, interruptible loads are negotiated, commensurate new capacity and/or transmission is built, or some combination of these options. Similarly, depending on the cooling technology and geographic location of new data centers, they could threaten water adequacy in water scarce regions. This webinar will provide an overview of the interactions between energy and AI and highlight two MSD projects exploring the grid and water implications of new data centers to support AI. Presenters : Dr. Casey Burleyson (Pacific Northwest National Laboratory); Dr. Stephanie Morris (Pacific Northwest National Laboratory); Kendall Mongird (Pacific Northwest National Laboratory) Moderator: Patrick M. Reed (MSD CoP Facilitation Team) This webinar was held on: June 16th, 2025 from 1-2 PM EST.

Artificial Intelligence↗

DOE OSTI2018

Nitrogen-doped nanostructured porous carbon derived from monosodium glutamate for high-performance lithium sulfur battery

Highlights: N-doped porous carbon nanosheets were prepared by a low-cost carbonization approach. The product possesses a special micro/mesoporous structure with high surface area. The S/NPCN-800 exhibits excellent electrochemical cycling and rate performance. The enhancement is attributed to synergistic effect of hierarchical porous structure and N-doping. - Abstract: Carbon host materials play an important role in improving the electrochemical performances of lithium-sulfur batteries. In this work, we have successfully prepared nitrogen-doped porous carbon nanosheets (NPCN) by using low-cost raw materials (monosodium glutamate) via a facile carbonization approach without any activation process. The obtained NPCN-800 possesses a special micro/mesoporous structure, with a relatively high BET surface area and appropriate nitrogen doping. By employing the NPCN-800 as a reservoir to impregnate sulfur as the cathode material of lithium-sulfur batteries, the resulting sulfur/carbon composite with 65.5 wt% sulfur exhibits an initial discharge capacity of 1070 mAh g{sup −1} at 0.2 C and enhanced capacity retention of 680 mAh g{sup −1} after 150 cycles. Moreover, a capacity of 452 mAh g{sup −1} at 0.5 C is achieved over 200 cycles with 98.6% Coulombic efficiency. The superior electrochemical performance is attributed to the synergistic effect of the hierarchical porous structure (physisorption) and N-doping (chemisorption).

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2020

Fluorinated Covalent Organic Frameworks: A Novel Pathway to Enhance Hydrogen Sorption and Control Isosteric Heats of Adsorption; HyMARC Seed Project Final Report

Organic framework materials, as a unique sub-class of carbon-based sorbents, have gained increasing attention for promising attributes toward gas storage. Calculations of the hydrogen capacity of optimized frameworks show potential to achieve greater than 60 g/L storage of hydrogen, placing metal-organic frameworks (MOFs) and COFs near the top of the class of porous materials. However, at the ensemble level, poor stacking creates a quasi-amorphous material with low structural integrity and low effective surface area. The chemical versatility of COFs allows for additional methods for producing long-range order that specifically target the inter-layer interactions in COFs but that leave key pore-accessible linker sites open. These modifications (either during synthesis or post-synthetic) enable a host of strategies to both improve crystalline order for more stable and higher surface, as well as add metals with open coordination for enhanced H 2 binding enthalpy.

08 HYDROGEN↗

DOE OSTI2016

Final Report: “Energetics of Nanomaterials”

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗