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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Optical trapping and manipulation of single particles for MDP

This two-year project, conducted under Grant Number DE-SC0021030, focused on the development and application of advanced optical trapping and manipulation technologies to study magnetized dusty plasma (MDP) systems and enhance diagnostic capabilities at the Magnetized Dusty Plasma Experiment (MDPX) facility at Auburn University. The central objective was to enable precise, non-invasive control and measurement of single particles within plasma environments, thereby addressing key limitations in existing plasma diagnostic techniques.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Atomic Manipulation of Single Erbium on GaAs(110): From Adatom Motion to Creation and Control of Bistable Substitutions

We demonstrate atomic-scale control over the position and configuration of single erbium (Er) atoms at the GaAs(110) surface using scanning tunneling microscopy (STM). By applying voltage pulses from the STM tip, we drive Er adatoms to move sequentially among three distinct adsorption sites and controllably substitute into Ga lattice sites. The resulting substitutional Er atoms exhibit two isoelectronic configurations that differ by less than one angstrom in lateral position and can be reversibly switched by additional voltage pulses. Differential conductance spectroscopy shows differences in the unoccupied local electronic states for the two substitutional configurations, and an absence of mid-gap states. Preliminary density functional theory (DFT) calculations support these findings, identifying the most stable adsorption and substitutional sites, their relative binding energies, charge states, and local density of states (LDOS) characteristics. Together, the experimental and theoretical results establish a method for precise, reversible manipulation of rare-earth dopants at semiconductor surfaces, opening a pathway to engineer atomic-scale quantum and optoelectronic functionalities.

Poche, Steven [Ohio State University]↗
DOE OSTI2024

Manipulating Spin–Lattice Coupling in Layered Magnetic Topological Insulator Heterostructure via Interface Engineering

Induced magnetic order in a topological insulator (TI) can be realized either by depositing magnetic adatoms on the surface of a TI or engineering the interface with epitaxial thin film or stacked assembly of 2D van der Waals (vdW) materials. Herein, the observation of spin-phonon coupling in the otherwise non-magnetic TI Bi 2 Te 3 is reported, due to the proximity of FePS 3 (an antiferromagnet (AFM), T N ≈ 120 K), in a vdW heterostructure framework. Temperature-dependent Raman spectroscopic studies reveal deviation from the usual phonon anharmonicity originated from spin-lattice coupling at the Bi 2 Te 3 /FePS 3 interface at/below 60 K in the peak position (self-energy) and linewidth (lifetime) of the characteristic phonon modes of Bi 2 Te 3 (106 and 138 cm –1 ) in the stacked heterostructure. The Ginzburg-Landau (GL) formalism, where the respective phonon frequencies of Bi 2 Te 3 couple to phonons of similar frequencies of FePS 3 in the AFM phase, is adopted to understand the origin of the hybrid magneto-elastic modes. At the same time, the reduction of characteristic TN of FePS 3 from 120 K in isolated flakes to 65 K in the heterostructure, possibly due to the interfacial strain, which leads to smaller Fe-S-Fe bond angles as corroborated by computational studies using density functional theory (DFT). Besides, inserting hexagonal boron nitride within Bi 2 Te 3 /FePS 3 stacking regains the anharmonicity in Bi 2 Te 3 . As a result, controlling interfacial spin-phonon coupling in stacked heterostructure can have potential application in surface code spin logic devices.

36 MATERIALS SCIENCE↗
DOE OSTI2024

3D‐Mapping and Manipulation of Photocurrent in an Optoelectronic Diamond Device

Abstract Establishing connections between material impurities and charge transport properties in emerging electronic and quantum materials, such as wide‐bandgap semiconductors, demands new diagnostic methods tailored to these unique systems. Many such materials host optically‐active defect centers which offer a powerful in situ characterization system, but one that typically relies on the weak spin‐electric field coupling to measure electronic phenomena. In this work, charge‐state sensitive optical microscopy is combined with photoelectric detection of an array of nitrogen‐vacancy (NV) centers to directly image the flow of charge carriers inside a diamond optoelectronic device, in 3D and with temporal resolution. Optical control is used to change the charge state of background impurities inside the diamond on‐demand, resulting in drastically different current flow such as filamentary channels nucleating from specific, defective regions of the device. Conducting channels that control carrier flow, key steps toward optically reconfigurable, wide‐bandgap optoelectronics are then engineered using light. This work might be extended to probe other wide‐bandgap semiconductors (SiC, GaN) relevant to present and emerging electronic and quantum technologies.

Wood, Alexander A.↗
DOE OSTI2025

Manipulating the Assembly and Architecture of Fibrillar Silk

Silk is a unique and exceptionally strong biological material. However, no synthetic method has yet come close to replicating the properties of natural silk. This shortfall is attributed to an insufficient understanding of both silk nanofibril structure and the mechanism of formation. Here in situ atomic force microscopy (AFM) and photo-induced force microscopy (PiFM) is utilized to investigate the formation process and define the basic structural paradigm of individual silk nanofibrils. By visualizing the multistage process of silk nanofibril formation, the importance of conformational transformations along the assembly pathway is revealed. Unfolded silk structures initially accumulate into amorphous clusters, which then evolve into crystal nuclei via conformational transformation into β-crystallites. Nanofibril elongation then occurs through the attachment of silk molecules at a single end of the nanofibril tip; this is facilitated through the formation of a new amorphous cluster that then repeats the aforementioned conformational transformation. However, enzymatic digestion of the amorphous regions leads to direct, rapid elongation of β-crystalline fibers. These findings imply that the energy landscape is characterized by shallow minima associated with intermediate states, which can be eliminated by introducing β-crystallites, and motivate research into the directed modification of the silk assembly pathway to select for features beneficial to specific applications.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Manipulation of Emergent Collective Excitations via Composition Control in Mixed MPX 3 Correlated 2D Antiferromagnets

Transition metal (i.e., Mn, Fe, Cr) and chalcogen (Se) substituents are introduced into single-crystalline NiPS 3 , and the evolution of the two emergent quasi-particle excitations characteristic to the XXZ correlated antiferromagnetism of NiPS 3 (i.e., spin orbit entangled exciton (SOX) and two-magnon scattering (2M )) are investigated as functions of substituent concentration through comprehensive room- and low-temperature photoluminescence (PL) and Raman spectroscopy studies. These findings are further correlated with the magnetic properties of the same set of compounds reported in prior studies. The work revealed that the SOX emission intensities and linewidths are mainly controlled by the magnetic anisotropy and spin orientations, and are strongly suppressed by the introduction of substituents. The suppression depends on the type of substituent, with Fe affecting the SOX emission more than Mn and Cr. The 2 M scattering is linked to short-range correlations and exhibits greater resiliency against metal atom substitution. While the 2M peak at low temperature gets suppressed and red-shifted in frequency with increasing concentrations of all the substituents, Fe induces the weakest suppression compared to all other substituents. Altogether, these findings revealed the introduction of substituents as a powerful route to control the emergent collective excitations in NiPS 3 and mixed-MPX 3 materials.

2D magnet↗
DOE OSTI2026

Manipulating Na/TM Ratio‐Driven Structural Heterogeneity of O3‐NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Cathode for High‐Voltage Sodium‐Ion Batteries

The stability of O3-type NaNi 1/3 Fe 1/3 Mn 1/3 O 2 under high-voltage cycling is dictated by how synthesis encodes lattice strain and redox heterogeneity. Here, in this study, the role of Na:TM stoichiometry is systematically resolved by tuning the NaOH:precursor ratio during solid-state synthesis. The stoichiometric condition (Na:TM = 1.00) yields minimized microstrain, enabling uniform O3–P3 phase evolution and homogeneous multi-metal redox with preserved octahedral symmetry. In contrast, Na-excess compositions inherit disordered intermediates and heterogeneous distortion fields that trigger abrupt multiphase transitions and promote localized charge redistribution. In situ XRD captures the divergence in phase-transition pathways, TXM resolves particle-level redox heterogeneity, and XANES corroborates a stronger and more reversible Fe redox contribution at stoichiometry, shifting to diminished Fe participation and spatially inhomogeneous redox at higher Na content. These results establish Na:TM stoichiometry as a critical synthesis parameter controlling both structural coherence and redox stability. Electrochemically, the stoichiometric composition exhibits smooth voltage profiles with minimal polarization growth and retains nearly 80% of its initial capacity after 100 cycles even at an extended 4.2 V cutoff, whereas Na-excess compositions show significantly reduced initial coulombic efficiency and rapid voltage fade. Precise stoichiometric tuning provides a scalable route to defect-suppressed O3 frameworks, enabling structurally resilient, high-voltage sodium-layered cathodes.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Ligand‐Directed Actinide Oxo‐Bond Manipulation in Actinyl Thiacalix[4]arene Complexes

Abstract Understanding the chemistry of the inert actinide oxo bond in actinyl ions AnO 2 2+ is important for controlling actinide behavior in the environment, during separations, and in nuclear waste (An=U, Np, Pu). The thioether calixarene TC4A (4‐ tert ‐butyltetrathiacalix[4]arene) binds equatorially to the actinyl cation forming a conical pocket that differentiates the two trans‐ oxo groups. The ‘ate’ complexes, [A] 2 [UO 2 (TC4A)] (A=[Li(DME) 2 ], HNEt 3 ) and [HNEt 3 ] 2 [AnO 2 (TC4A)] (An=U, Np, Pu), enable selective oxo chemistry. Silylation of the U VI oxo groups by bis(trimethylsilyl)pyrazine occurs first at only the unencapsulated exo oxo and only one silylation is needed to enable migration of the endo oxo out of the cone, whereupon a second silylation affords the stable U IV cis‐ bis(siloxide) [A] 2 [U(OSiMe 3 ) 2 (TC4A)]. Calculations confirm that only one silylation event is needed to initiate oxo rearrangement, and that the putative cis dioxo isomer of [UO 2 (TC4A)] 2− would be stable if it could be accessed synthetically, at only 23 kcal.mol −1 in energy above the classical trans dioxo. Calculations for the transuranic cis [AnO 2 (TC4A)] 2− (An=Np, Pu) are at higher energies, 30–35 kcal.mol −1 , retaining the U complexes as the more obvious target for a cis ‐dioxo actinyl ion. The aryloxide (OAr) groups of the macrocycle are essential in stabilizing this as‐yet unseen uranyl geometry as further bonding in the TC4A U‐O Ar groups stabilizes the U=O ‘yl’ bonds, explaining the stability of the putative cis [UO 2 (TC4A)] 2− in this ligand framework.

Pyrch, Mikaela M. [College of Chemistry University↗
DOE OSTI2025

Ligand‐Directed Actinide Oxo‐Bond Manipulation in Actinyl Thiacalix[4]arene Complexes

Understanding the chemistry of the inert actinide oxo bond in actinyl ions AnO2 2+ is important for controlling actinide behavior in the environment, during separations, and in nuclear waste (An=U, Np, Pu). The thioether calixarene TC4A (4-tert-butyltetrathiacalix[4]arene) binds equatorially to the actinyl cation forming a conical pocket that differentiates the two trans-oxo groups. The 'ate' complexes, [A]2[UO2(TC4A)] (A=[Li(DME)2], HNEt3) and [HNEt3]2[AnO2(TC4A)] (An=U, Np, Pu), enable selective oxo chemistry. Silylation of the UVI oxo groups by bis(trimethylsilyl)pyrazine occurs first at only the unencapsulated exo oxo and only one silylation is needed to enable migration of the endo oxo out of the cone, whereupon a second silylation affords the stable UIV cis-bis(siloxide) [A]2[U(OSiMe3)2(TC4A)]. Calculations confirm that only one silylation event is needed to initiate oxo rearrangement, and that the putative cis dioxo isomer of [UO2(TC4A)]2- would be stable if it could be accessed synthetically, at only 23 kcal.mol-1 in energy above the classical trans dioxo. Calculations for the transuranic cis[AnO2(TC4A)]2- (An=Np, Pu) are at higher energies, 30-35 kcal.mol-1, retaining the U complexes as the more obvious target for a cis-dioxo actinyl ion. The aryloxide (OAr) groups of the macrocycle are essential in stabilizing this as-yet unseen uranyl geometry as further bonding in the TC4A U-OAr groups stabilizes the U=O 'yl' bonds, explaining the stability of the putative cis[UO2(TC4A)]2- in this ligand framework.

Pyrch, Mikaela M↗
DOE OSTI2024

Manipulating symmetry-breaking charge separation employing molecular recognition

The exploration of symmetry-breaking charge separation (SB-CS) is imperative when designing functional light-harvesting materials. Past explorations, however, have been confined to covalent systems, more often than not requiring complicated/demanding syntheses and facing inconvenient regulation of charge transfer processes. Here, in this work, we present a concept that regulates the efficiency of SB-CS through molecular recognition utilizing a pyridinium-based cyclophane as a host. This host undergoes photo-driven excited-state SB-CS. By employing different guests with distinct frontier molecular orbital energy levels, we have achieved comprehensive control of electron transfer pathways in the cyclophane, modulating between accelerated (>10-fold) intramolecular SB-CS involving superexchange and direct intermolecular electron transfer between the host and guest. The improvement in SB-CS efficiency results in catalytic activity for the photo-oxidation of a sulfur-mustard simulant. This research offers an opportunity for tuning SB-CS by utilizing molecular recognition, which holds the potential for achieving precise regulation without complicated organic syntheses.

charge transfer↗
DOE OSTI2025

Controlling mechanical properties of laser powder bed fused AlSi10Mg through manipulation of laser scan rotation

The microstructure and mechanical properties of laser powder bed fused (LPBF) AlSi10Mg alloys can be controlled by many processing parameters. This study focuses on the scan rotation angle, α, between adjacent layers, and establishes the relationship between α and tensile behavior of the as-built LPBF-processed AlSi10Mg alloy. Near-full density cubic coupons were manufactured using the same processing parameters but with systematic variation of α from 0° to 90°. Microscopic observations and X-ray diffraction analysis showed that differences among various coupons mainly include orientations of the melt pools with respect to the build direction and development of the crystallographic texture. The α=0° coupon and α=30° coupon showed the highest and lowest texture index, although the overall crystallographic texture was mild. Tensile specimens were manufactured horizontally and vertically using either α=0° or α=30°, but with various first layer laser direction with respect to the build plate. Notably, the α=0° specimen that was tested along the laser scan direction showed the largest yield strength (283 MPa) and highest tensile ductility (10.1 %). Quantitative image analysis and fractography were performed on all specimens. Results showed that the melt pool orientation with respect to the tensile direction affected the tensile behavior across the different specimens. This was closely related to the localized strain distribution within the melt pool and along the melt pool boundary for the different melt pool orientations observed. Further, these results demonstrate that the laser scan rotation angle between layers can be used to fine tune the mechanical properties of LPBF AlSi10Mg alloy.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Nanorod Pair Complexes Manipulated via Magnetic Casimir Forces

Here, we demonstrate a route to modulate Casmir–Lifshitz interactions between anisotropic nanoparticles and magnetic fluids. By semiclassical quantum electrodynamics, we study ground state dispersion forces for cylindrical dielectric nanorods made of polystyrene (PS) and zinc oxide (ZnO) embedded in toluene-based host media with gold-coated magnetite nanoparticles and also predict magnetic contributions to the fully retarded excited state interaction. The variation in magnetic permeability enables tuning between repulsive and attractive interactions, and measurable magnetic Casimir traps are predicted between a pair of ZnO–PS nanoparticles whose equilibrium position can be modulated over an order of magnitude with a small variation in the size of the magnetite nanoparticle. This provides an alternative magnetic Casimir-effect pathway to reversibly tune quantum electromagnetic forces at the nanoscale for the assembly and enhancement of colloidal stability.

Excited-state interaction↗
DOE OSTI2025

Dimolybdenum Paddlewheel Complexes with Cation Binding Sites as Electrolyte Additives to Manipulate the Solid-Electrolyte Interphase at Lithium Metal Anodes

The use of electrolyte additives at millimolar loadings to control the surface chemistry of lithium metal anodes (LMAs) is a leading strategy to improve lithium metal batteries and promote electrosynthetic reactions. Whereas previous studies employed either inorganic or organic additives, in this study, we report the first organometallic additive, Mo 2 (mea) 4 [1, mea = 2-(2-methoxyethoxy)acetate], a dimolybdenum paddlewheel complex that is stable under Li plating conditions and features cation binding sites in the second coordination sphere that promote reversible Li + coordination. Binding of Li + ions to 1 induces immobilization of cationically charged aggregates (or products thereof) into the solid electrolyte interphase (SEI), imparting multiple beneficial functions. The modified SEI was found to protect the LMA against parasitic side reactions, produce modest but measurable improvements to Li plating properties (e.g., overpotential, surface structure, and Coulombic efficiency), and improve interfacial charge transport properties. Furthermore, the most notable benefit to battery cycling performance appears in calendar aging tests, which show that the presence of the additive protects the LMA from parasitic side reactions that would otherwise decrease overall cell cycling efficiency over time. Collectively, these data disclose a tactic for designing electrolyte additives using principles of organometallic synthesis.

Additives↗
DOE OSTI2025

Manipulating Excitonic Quantum Droplets in Two-Dimensional CdSe Nanoplatelets via Thickness and Core/Shell Morphology

Recently, photoexcitation of high-density 4 or 5 monolayer (ML) thick CdSe nanoplatelet films at temperatures below ~200K was observed to produce pump-intensitydependent, superlinear, progressively red-shifted light output due to amplified spontaneous emission (ASE) from polyexcitonic species, distinct from biexcitonic ASE. These polyexcitonic species comprise Coulombically bound multiexciton states, termed “quantum droplets”, that form when multiexciton binding energy exceeds thermal energy fluctuations. In this work, we investigate thinner samples as well as core/shell nanoplatelet films and find that the 3 ML sample supports quantum droplet ASE up to higher temperatures than the 4 or 5 ML whereas core/shell structures suppress this form of ASE even at very low sample temperatures despite observable biexcitonic ASE, suggesting that the reduced or repulsive Coulomb binding energy of multiple excitons suppresses quantum droplets. These findings help to add understanding of routes to harness quantum droplet optical nonlinearities.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Manipulating the Second Coordination Shell of Single-Atom Fe for Enhanced Fenton Reaction

While current methods use oxidizable metals as electron donors to effectively reduce Fe 3+ , they suffer from the irreversible oxidation of these metals, ultimately compromising the catalyst’s longevity. To address this challenge, we engineered the second coordination shell of a single-atom Fe center by doping boron (B) onto a graphene-based support (Fe 1 /B-graphene) and utilized H 2 O 2 as the electron source for efficient Fe 2+ regeneration. Experimental results, supported by theoretical calculations, revealed that the Fe–O–B motif functions like a micro galvanic cell, with intermediary O atoms facilitating electron transfer between electrodes. Specifically, electrons consumed during H 2 O 2 activation at Fe 1 sites (positive electrode) are replenished by electrons extracted from H 2 O 2 at B atoms (negative electrode), where the activation energy for H 2 O 2 oxidation is significantly lower than that at Fe 1 sites. This study offers inspirational insights into the design of Fenton catalysts through precise regulation of the second coordination shell, demonstrating the potential of tailoring the outer coordination environment of single-atom catalysts to enhance catalytic performance across various reactions.

36 MATERIALS SCIENCE↗