A5029274949- Magnetic and transport properties of perovskites and related materials
- Advanced Memory and Neural Computing
- Transition Metal Oxide Nanomaterials
- Quantum and electron transport phenomena
- Electronic and Structural Properties of Oxides
- Molecular Junctions and Nanostructures
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor materials and devices
- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Surface and Thin Film Phenomena
- Surface Chemistry and Catalysis
- Organic Electronics and Photovoltaics
- Advanced Condensed Matter Physics
- Semiconductor Quantum Structures and Devices
- Neural dynamics and brain function
- Magneto-Optical Properties and Applications
- Quantum Dots Synthesis And Properties
- Theoretical and Computational Physics
- Machine Learning in Materials Science
- Magnetic Properties of Alloys
- Magnetic properties of thin films
- Rare-earth and actinide compounds
- X-ray Diffraction in Crystallography
- Electrocatalysts for Energy Conversion
HRL Laboratories (United States)
2014-2023
Harvard University
2011-2014
Harvard University Press
2014
Princeton University
2007-2011
Georgia Institute of Technology
2007
Qubits encoded in a decoherence-free subsystem and realized exchange-coupled silicon quantum dots are promising candidates for fault-tolerant computing. Benefits of this approach include excellent coherence, low control crosstalk, configurable insensitivity to certain error sources. Key difficulties that entangling gates require large number pulses high-yielding dot arrays. Here we show device made using the single-layer etch-defined gate electrode architecture achieves both required...
Vanadium dioxide is a correlated electron system that features metal-insulator phase transition (MIT) above room temperature and of interest in high speed switching devices. Here, we integrate VO2 into two-terminal coplanar waveguides demonstrate large resistance modulation the same magnitude (>10^3) both electrically (i.e. by bias voltage, referred to as E-MIT) thermally (T-MIT) driven transitions. We examine transient characteristics E-MIT observe two distinguishable time scales for...
Spin-based silicon quantum dots are an attractive qubit technology for information processing with respect to coherence time, control, and engineering. Here we present exchange-only Si device platform that combines the throughput of CMOS-like wafer versatility direct-write lithography. The technology, which coin "SLEDGE", features dot-shaped gates patterned simultaneously on one topographical plane subsequently connected by vias interconnect metal lines. process design enables nontrivial...
Strongly correlated electron systems such as the rare-earth nickelates (RNiO3, R = element) can exhibit synapse-like continuous long term potentiation and depression when gated with ionic liquids; exploiting extreme sensitivity of coupled charge, spin, orbital, lattice degrees freedom to stoichiometry. We present experimental real-time, device-level classical conditioning unlearning using nickelate-based synaptic devices in an electronic circuit compatible both excitatory inhibitory neurons....
The rare-earth nickelates ($R$NiO${}_{3}$) exhibit interesting phenomena such as unusual antiferromagnetic order at wave vector q $=$ (\textonehalf{}, 0, \textonehalf{}) and a tunable insulator-metal transition that are subjects of active research. Here we present temperature-dependent transport measurements the resistivity, magnetoresistance, Seebeck coefficient, Hall coefficient (${R}_{\mathrm{H}}$) epitaxial SmNiO${}_{3}$ thin films with varying oxygen stoichiometry. We find from room...
The rare-earth nickelates (LnNiO3, Ln = lanthanide) are interesting from both fundamental and applied perspectives, but synthesis remains a bottleneck to research due their thermodynamic instability. Here we report the of SmNiO3 thin films on oxidized silicon wafers by physical vapor deposition followed high pressure oxygen annealing at intermediate temperatures. annealed show an insulator–metal transition characteristic bulk samples. Our experimental observations then allow us estimate...
The authors discuss an overview of strongly correlated electron systems and metal-insulator transition (MIT) oxide materials. Microwave applications MIT materials are also introduced. This offers a vision for future microwave devices with adaptive capabilities.
Doping is essential to the control of electronic structure and conductivity semiconductor materials. Whereas doping inorganic semiconductors well established, organic molecular still relatively poorly understood. Using scanning tunneling microscopy, we investigate, at scale, surface subsurface tetrafluoro-tetracyanoquinodimethane $p$-dopants in prototypical pentacene. Surface dopants diffuse pentacene vacancies appear as negatively charged centers, consistent with standard picture an ionized...
SmNiO3 (SNO) thin films were deposited on LaAlO3 (LAO), SrTiO3, SrLaAlO4, Si, and Al2O3 (sapphire) substrates by RF magnetron sputtering studies conducted to understand how film structure composition influence the insulator-metal transition properties. It is observed that compressive strain induces insulator metal (MIT), while tensile suppresses it. In case of non-epitaxial films, semiconducting behavior obtained sapphire over a broad temperature range, heavily-doped Si substrate; an MIT...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Sieu D. Ha, Ulrich Vetter, Jian Shi, Shriram Ramanathan; Electrostatic gating of metallic insulating phases in SmNiO3 ultrathin films. Appl. Phys. Lett. 6 May 2013; 102 (18): 183102. https://doi.org/10.1063/1.4804142 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote...
We implement a technique for measuring the singlet-triplet energy splitting responsible spin-to-charge conversion in semiconductor quantum dots. This method, which requires fast, single-shot charge measurement, reliably extracts an limits of both large and small splittings. perform this on undoped, accumulation-mode Si/SiGe triple-quantum dot find that measured varies smoothly as function confinement gate biases. Not only does demonstration prove value having $in~situ$ excited-state...
The promise of quantum computation is contingent upon physical qubits with both low gate error rate and broad scalability. Silicon-based spins are a leading qubit platform, but demonstrations to date have not utilized fabrication processes capable extending arrays in two dimensions while maintaining complete control individual spins. Here, we implement an interconnect process, common semiconductor manufacturing, multiple back-end-of-line layers show extendable two-dimensional array fully...
The correlated oxide SmNiO3 (SNO) exhibits an insulator to metal transition (MIT) at 130 °C in bulk form. We report on synthesis and electron transport SNO films deposited LaAlO3 (LAO) Si single crystals. X-ray diffraction studies show that compressively strained single-phase grows epitaxially LAO while Si, mixed phases are observed. MIT is observed resistance-temperature measurements grown both substrates, with charge in-plane for LAO/SNO out-of-plane Si/SNO films. Electrically driven...
The mechanisms of molecular doping in organic electronic materials are explored through investigation pentacene $p$-doped with molybdenum trioxide $({\text{MoO}}_{3})$. Doping is confirmed ultraviolet photoelectron spectroscopy. Isolated dopants imaged at the scale using scanning tunneling microscopy (STM) and effects due to localized holes observed. results demonstrate that donated charges by counterpotential ionized ${\text{MoO}}_{3}$-doped pentacene, generalizing similar previously...
We study the time-fluctuating magnetic gradient noise mechanisms in pairs of Si/SiGe quantum dots using exchange echo spectroscopy. find through a combination spectral inversion and correspondence to theoretical modeling that quadrupolar precession 73Ge nuclei play key role spin-echo decay time T2, with characteristic dependence on field width Si well. The peaks appear at fundamental first harmonic Larmor resonance, superimposed over 1/f due 29Si dipole-dipole dynamics, are dependent...
Self-assembled monolayers of E-stilbene-4-thiolate (SAM1), E-4'-(ethoxy)stilbene-4-thiolate (SAM2), and E-4'-(dimethylamino)stilbene-4-thiolate (SAM3) on Au(111) have been obtained from reaction ethanol solutions the corresponding S-acetyl derivatives with gold substrates. A combination X-ray photoelectron spectroscopy, ellipsometry, infrared reflection absorption spectroscopy indicates that are dense (ca. 3.3 x 10(14) molecules/cm(2)) long molecular axes thiolates approximately...
Scanning tunneling microscopy was used to study the morphological behavior of 1−2 monolayers (ML) 5,6,11,12,17,18-hexaazatrinaphthylene (HATNA) deposited on Au(111). The first ML consisted molecules flat surface, arranged in one three different ordered phases depending annealing parameters. second assumed an upright orientation and tended order only if layer disordered. spectroscopy HATNA compared ultraviolet photoemission inverse 80 Å amorphous HATNA. There is good agreement between...
Interaction between the lattice and orbital degrees of freedom not only makes rare-earth nickelates unusually ``bad metal,'' but also introduces a temperature-driven insulator-metal phase transition. Here we investigate this transition in thin films ${\mathrm{SmNiO}}_{3}$ using slow time-dependent fluctuations (noise) resistivity. The normalized magnitude noise is found to be extremely large, being nearly eight orders higher than common disordered metallic systems, indicates electrical...
Correlated oxides that exhibit metal–insulator phase transitions are emerging as potential candidates for switching devices. One such material is SmNiO3, which has a transition temperature above room (∼400 K in bulk crystals). In this work, we study temperature- and bias-dependent conduction mechanisms epitaxial polycrystalline SmNiO3 thin films. both cases, at low electric field observe thermally assisted hopping through defect states with activation energies of ∼170 meV ∼270 meV,...
Precise nanofabrication represents a critical challenge to developing semiconductor quantum-dot qubits for practical quantum computation. Here, we design and train convolutional neural network interpret scanning electron micrographs quantify qualitative features affecting device functionality. The high-throughput strategy is exemplified by optimizing model lithographic process within five-dimensional space demonstrating robust approach address proximity effects. results emphasize the...