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Fine structure of current noise spectra in nanoelectromechanical resonators

Here, we study the frequency-dependent noise of a suspended carbon nanotube quantum dot nanoelectromechanical resonator induced by electron-vibration coupling. Using a rigorous Keldysh diagrammatic technique, we establish a formal framework connecting the vibrational properties to electrical measurements. We find that the noise power spectrum exhibits a narrow resonant peak at the frequency of the vibrational modes. However, this fine structure tends to disappear due to a coherent cancellation effect when the tunneling barriers are tuned to a symmetric point. Notably, measuring the electrical current noise spectra provides a sensitive alternative method for detecting the damping and dephasing of quantum vibrational modes.

Electric measurements

High temperature electrical property measurements of ceramics

Emerging applications in energy and aerospace systems require high quality data on the high temperature electrical properties of ceramics, particularly oxides, to guide material selection, design, and modeling. This presentation demonstrates the functionality of a specially designed sample fixture that enables electrical measurements to be conducted up to temperatures as high as 1600°C. Utilizing the mismatch in the coefficient of thermal expansion between two materials, a purely mechanical method for establishing electrical contact in the van der Pauw geometry is used to measure the bulk resistivity of ceramic materials. Measurements conducted on a number of common high temperature materials will be presented, including 20 mol % Gd-doped cerium oxide. Measurements are performed using multiple techniques and compared to literature values finding excellent agreement. The approach described in this work enables the van der Pauw method to be applied to many ceramic materials over a wide range of temperatures and environments.

Cann, David P.

Synthesis, Structures, and Transport Properties of Quaternary Ba–Ag– Tr –As Materials ( Tr = Ga, In)

The synthesis, structures, and properties of two quaternary barium–arsenide materials are presented. The first, Ba 4 Ag 2.3 In 1.7 As 8 , is a novel material with the monoclinic unit cell ( P 2 1 / m space group). The layered crystal structure of Ba 4 Ag 2.3 In 1.7 As 8 may be considered a lower‐symmetry, distorted analog of the LaCuSb 2 structure. The structure features a rare As fragment, cis‐trans As chains along the [010] direction. Large crystals of Ba 4 Ag 2.3 In 1.7 As 8 can be grown from Bi flux and are used for subsequent transport property measurements. Electrical resistivity and heat capacity properties are reported, establishing Ba 4 Ag 2.3 In 1.7 As 8 as a metallic phase. The second material, Ba 4 AgGa 5 As 8 , is a 3D material that crystallizes in the orthorhombic unit cell (noncentrosymmetric and polar Iba 2 space group). Expanding upon its original discovery, the optimized synthetic profile for single‐phase polycrystalline samples as well as transport properties relevant to thermoelectric applications are presented. Ba 4 AgGa 5 As 8 exhibits a high Seebeck coefficient of 290 μV K −1 at room temperature, indicative of lower carrier concentrations typical for nonmetallic phases. Electrical resistivity measurements also affirm conventional semiconducting behavior for Ba 4 AgGa 5 As 8 .

Kyveryga, Victoria [Department of Chemistry Iowa S

Evidence of Superconductivity in Electrical Resistance Measurements of Hydrides Under High Pressure

In the standard van der Pauw four-probe configuration commonly used for electrical resistance measurements, including those of hydrogen-rich samples at high pressures, the application of electrical current through one pair of leads while measuring voltage difference across another pair is a fundamental practice (see the inset in Fig. 1c). In the scenario described in Ref. [5], where electrical resistance vanishes due to disconnection between current and voltage probes or due to an onset of giant magnetoresistance in parts of the sample, it is crucial to consider the implications across different probe orientations: while one orientation may indeed result in vanishing electrical resistance, a divergence of the electrical resistance towards infinity will be observed in an alternative orientation where the applied current pattern is rotated a quarter turn (see the scheme on the inset in Fig. 1c). It is imperative to acknowledge that experimental data encompassing all possible probe orientations are essential for eliminating artifacts and assessing sample homogeneity.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND

Measurement of electrical characteristics of Ge-based diodes with thermal GeO2 films exposed to controlled humidity conditions

We investigated the impact of the interaction between gas-phase water molecules and thermally oxidized GeO2 on Ge on the performance of metal–oxide–semiconductor (MOS) structures. A vacuum-integrated setup was developed to form MOS diodes with a GeO2/Ge structure that had been exposed to controlled humidity conditions and to subsequently measure their electrical characteristics in situ. The capacitance–voltage (C–V) curves exhibited a significant negative shift, indicating the generation of positive charges at the GeO2/Ge interface when the GeO2 surface was exposed to humidity levels above approximately 1%. According to a previous study using electron spectroscopy, this threshold corresponds to the humidity level at which molecular water begins to grow on a GeO2/Ge structure. It is likely that gas-phase water molecules infiltrating the GeO2 film bind to local OH sites via hydrogen bonding, leading to the formation of positive fixed charges at the GeO2/Ge interface.

Sano, Shuto

ResStock Measure Documentation: Electric Vehicle Adoption With Level 1 Charging

This report is part of a series describing different ResStock (TM) measures. "Measures" refers to energy efficiency retrofits that can be applied to buildings during modeling. This documentation covers the "Electric Vehicle Adoption With Level 1 Charging" measure upgrade methodology and briefly discusses key results.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI

ResStock Measure Documentation: Electric Vehicle Adoption With Level 2 Charging

This report is part of a series describing different ResStock (TM) measures. "Measures" refers to energy efficiency retrofits that can be applied to buildings during modeling. This documentation covers the "Electric Vehicle Adoption With Level 2 Charging" measure upgrade methodology and briefly discusses key results.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI

ResStock Measure Documentation: Electric Vehicle Adoption With Level 2 Charging and Demand Flexibility

This report is part of a series describing different ResStock measures. "Measures" refers to energy efficiency retrofits that can be applied to buildings during modeling. This documentation covers the "Electric Vehicle Adoption With Level 2 Charging and Demand Flexibility" measure upgrade methodology and briefly discusses key results.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI

Real-time steerable frequency-stepped Doppler backscattering (DBS) system for local helicon wave electric field measurements on the DIII-D tokamak

A new frequency-stepped Doppler backscattering (DBS) system has been integrated into a real-time steerable electron cyclotron heating launcher system to simultaneously probe local background turbulence (f < 10 MHz) and high-frequency (20–550 MHz) density fluctuations in the DIII-D tokamak. The launcher allows for 2D steering (horizontally and vertically) over wide angular ranges to optimize probe location and wavenumber response. The vertical steering can be optimized during a discharge in real time. The new DBS system employs a programmable frequency synthesizer with adjustable dwell time as a source to launch either O or X-mode polarized millimeter waves. This system can step in real-time over the entire E-band frequency range (60–90 GHz). This combination of capabilities allows for the diagnosis of the complex internal spatial structure of high power (>200 kW) helicon waves (476 MHz) injected from an external antenna during helicon current drive experiments in DIII-D. Broadband density fluctuations around the helicon frequency are observed during real-time scans of measurement location and wavenumber during these experiments. Analysis indicates that these broadband high-frequency fluctuations are a result of backscattering of the DBS millimeter-wave probe beam from plasma turbulence modulated by the helicon wave. It is observed that background turbulence is effectively locally “tagged” with the helicon wave electric field, forming images of the turbulent spectrum in the overall density fluctuation spectrum that appear as high-frequency sidebands of the turbulence. These observations of background turbulence and high-frequency fluctuations open up the possibility of monitoring local helicon wave amplitude by comparing the high-frequency signal amplitude to the simultaneously measured background turbulence. In combination with the real-time measurement location and wavenumber scanning capabilities (offered by real-time frequency-stepping and steering), this allows rapid determination of the spatial distribution of the helicon wave power during steady-state plasma operation.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Application of Banking Scoring and Rating for Coherent Risk Measures in Electricity Systems ABSCORES

This project developed a framework for asset and system risk management that can be incorporated into current electricity system operations to improve economic efficiency and establish an Electric Assets Risk Bureau. We leveraged scoring and ratings from banking and financial institutions alongside current optimization methods in dispatching power systems to help system operators and electricity markets schedule resources. This approach is based on the observation that there are major discrepancies between the power scheduled by a system operator and the actual power generated/consumed. These discrepancies—exacerbated by unplanned contingencies (e.g., natural disasters)—are caused by multiple factors, including the different financial, environmental and risk preferences of power producers, consumers, and aggregators. We developed a framework that counteracts two failures in electricity system operations: imperfect information and missing markets for products. The technical approach included five tasks. Tasks 1 and 2 supported the development of risk scores at the asset level with historical data collected for this project. Tasks 3, 4, and 5 incorporated scoring into decision-making at the system level. The proposed effort achieved PERFORM's Program Objectives because the proposed outputs and algorithms do not exist in the electricity industry and are an innovative approach to managing risk. Since the acknowledged need to better assess and act upon risk profiles for grid assets has not been met by the industry, this project will also impact ARPA-E's Mission Areas, including improving energy efficiency and giving the U.S. a technological lead in advanced energy technologies.

29 ENERGY PLANNING, POLICY, AND ECONOMY

What more can be done with XPS? Highly informative but underused approaches to XPS data collection and analysis

Because of the importance of surfaces and interfaces in many scientific and technological areas, the use of x-ray photoelectron spectroscopy (XPS) has been growing exponentially. Although XPS is being used to obtain useful information about the surface composition of samples, much more information about materials and their properties can be extracted from XPS data than commonly obtained. This paper describes some of the areas where alternative analysis methods or experimental design can obtain information about the near-surface region of a sample, often information not available in other ways. Experienced XPS analysts are familiar with many of these methods, but they may not be known to new or casual XPS users, and sometimes, they have not been used because of an inappropriately assumed complexity. The information available includes optical, electronic, and electrical properties; nanostructure; expanded chemical information; and enhanced analysis of biological materials and solid/liquid interfaces. Many of these analyses can be conducted on standard laboratory XPS systems, with either no or relatively minor system alterations. Topics discussed include (1) considerations beyond the “traditional” uniform surface layer composition calculation, (2) using the Auger parameter to determine a sample property, (3) use of the D parameter to identify sp 2 and sp 3 carbon information, (4) information from the XPS valence band, (5) using cryocooling to expand range of samples that can be analyzed and minimize damage, and (6) using electrical potential effects on XPS signals to extract chemically resolved electrical measurements including band alignment and electrical property information.

Baer, Donald R. [Pacific Northwest National Labora

Downscaling of Non-Van der Waals Semimetallic W 5 N 6 with Resistivity Preservation

The bulk phase of transition metal nitrides (TMNs) has long been a subject of extensive investigation due to their utility as coating materials, electrocatalysts, and diffusion barriers, attributed to their high conductivity and refractory properties. Downscaling TMNs into two-dimensional (2D) forms would provide valuable members to the existing 2D materials repertoire, with potential enhancements across various applications. Moreover, calculations have anticipated the emergence of uncommon physical phenomena in TMNs at the 2D limit. Here, in this study, we use the atomic substitution approach to synthesize 2D W 5 N 6 with tunable thicknesses from tens of nanometers down to 2.9 nm. The obtained flakes exhibit high crystallinity and smooth surfaces. Electrical measurements on 15 samples show an average electrical conductivity of 161.1 S/cm, which persists while thickness decreases from 45.6 to 2.9 nm. The observed weak gate-tuning effect suggests the semimetallic nature of the synthesized 2D W 5 N 6 . Further investigation of the conversion mechanism elucidates the crucial role of chalcogen vacancies in the precursor for initiating the reaction and strain in propagating the conversion. Our work introduces a desired semimetallic crystal to the 2D material library with mechanistic insights for future design of the synthesis.

2D electronics

Zero Resistance Ammetry (ZRA) Measurements of Sediment Electrochemical Gradients, Old Woman Creek, Ohio, USA, June–November 2022

This dataset contains raw and processed zero resistance ammetry (ZRA) measurements collected from wetland sediments at Old Woman Creek, a freshwater estuary on Lake Erie, Ohio, USA, between June and November 2022. Measurements were obtained using a vertically deployed electrode array positioned at multiple depths within the sediment profile to capture electrochemical gradients associated with microbial activity and sediment geochemistry. The raw dataset consists of parsed instrument log files containing timestamps, electrode pair identifiers, and measured electrical potential (mV). The processed dataset includes standardized and quality-controlled values with instrument saturation limits removed and timestamps converted to ISO 8601 format. Electrode line identifiers were mapped to physical depths, enabling interpretation of depth-resolved electrochemical gradients. Instrument saturation values (−2048, −2047, 2047, and 2048 mV) were identified as measurement limits and excluded from quantitative analyses. All data parsing, processing, and quality control steps are documented in an accompanying R Markdown script, ensuring full reproducibility from raw instrument logs to final datasets.

EARTH SCIENCE > AGRICULTURE > SOILS > ELECTRICAL C

Dual-Functional Thermocapacitive Heat Pump with Electrochemical Supercapacitors for Building Thermal Management and Energy Storage

Efficient heating and cooling technologies can help reduce the energy consumption and carbon emissions of buildings. This work explores the use of supercapacitive cells in a multifunctional, liquid-regenerated thermocapacitive heat pump that can provide electrical energy storage in addition to heating and cooling. A proof-of-concept prototype based on eight commercial supercapacitors and using deionized water as a liquid regenerator demonstrated cooling and energy storage capabilities. A peak cooling coefficient of performance (COPc) of 0.27 was achieved at a temperature drop of 0.24 K. The highest measured electrical energy storage density of the cells was 5.93 J cm-3, and the highest cooling power delivered relative to the volume of the cells was 0.58 mW cm-3. This work demonstrates the use of electrochemical energy storage devices in multifunctional equipment for thermal management in buildings.

25 ENERGY STORAGE

Thermodynamics, local structure, and transport of protons in triple-conducing oxide, BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ (BCFZY4411)

Triple-conducting oxides (TCOs) are an emerging class of mixed ionic and electronically conducting materials that show great promise for oxygen reduction/oxygen evolution (ORR/OER) electrocatalysis—primarily in high-temperature ceramic electrochemical cells— but also in aqueous alkaline environments. Their high activity is attributed, at least in part, to their ability to incorporate and transport three mobile charge carriers: protons, oxygen vacancies, and electron-holes Despite their promise, fundamental studies of TCOs are challenging, as transport dynamics from three charge carriers cannot be fully disentangled via traditional electrical measurement techniques. Characterizing proton dynamics in TCOs is particularly difficult as protons are generally the minority carrier, and their conduction response is typically obscured by the oxygen vacancies and electron holes. Here, we demonstrate successful isolation of the proton behavior in an archetypal TCO, BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3-δ (BCFZY4411), using a combination of non-electrical techniques. We determine proton uptake and oxygen non-stoichiometry (δ) using thermogravimetric analysis (TGA). X-ray absorption near edge structure (XANES) and neutron diffraction (ND) are used to validate the oxidation state of Co and the δ values obtained through TGA. We apply 1H solid-state magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) to provide insights into local structure, dynamics, and proton kinetics. Finally, the proton transport properties are further quantified using tracer isotope exchange with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Despite the very low proton concentrations in BCFZY4411 (<0.2% under most conditions), our analysis suggests that the oxygen Manuscript File Click here to view linked References 2 reduction and evolution reactions are nevertheless limited by the oxygen ion kinetics (e.g., oxygen surface exchange) rather than the proton kinetics at the reduced operating temperatures (<500 °C) that are targeted for electrochemical cell applications. These findings provide a comprehensive understanding of proton behavior in BCFZY4411 and pave the way for advancing the fundamental study of TCOs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH

Machine Learning Enabled Position Detection for 6.78 MHz UAV Wireless Power Transfer System

This paper presents a novel supervised machine learning (SML) approach for accurate position detection of the receiver coil in wireless power transfer (WPT) systems using only secondary-side electrical measurements, with applications in autonomous unmanned aerial vehicle (UAV) charging. The proposed method trains a supervised learning model to map measured secondary-side voltage and current features to the receiver’s spatial position with high precision. This enables an autonomous UAV to determine its location relative to the primary coil center, the optimal position for maximizing wireless charging efficiency. The sensing method is fully integrated into a standard WPT system, utilizing the same primary and secondary coils for both power transfer and position detection, thereby eliminating additional sensing hardware. The use of a 6.78 MHz operating frequency enhances positional sensitivity, as high-frequency near-field electromagnetic fields respond strongly to small spatial variations. Experimental validation is performed on a 30 W scaled prototype featuring a 210 mm × 140 mm primary coil, a 50 mm × 80 mm receiver coil, and a 15 mm air gap. Results demonstrate reliable position estimation and a strong correlation between predicted position and optimal coil alignment. This integrated framework unifying position detection and wireless charging offers a promising foundation for future autonomous electric vertical takeoff and landing (eVTOL) systems, enabling compact, hardware-efficient, and high-accuracy charging solutions.

Colak, Kerim [New York University]