publicationDate
stringlengths
1
2.79k
title
stringlengths
1
36.5k
abstract
stringlengths
1
37.3k
id
stringlengths
9
47
2013-10-14
Element spots in HgMn stars
A fraction of late B-type stars, the so-called HgMn stars, exhibit enhanced absorption lines of certain chemical elements, notably Hg and Mn, combined with an underabundance of He. For about a decade now the elements with anomalously high abundances in HgMn stars are known to be distributed inhomogeneously over the ste...
1310.3686v1
2013-11-12
Feasibility Study on SRF Cavity Improvement by Doping Method
In this article a new idea is proposed by PKU group to improve the RF superconductive property of niobium cavity. Rare earth elements like scandium and yttrium are doped into ingot niobium during the smelting processes. A series of experiments have been done since 2010, and the preliminary testing results show that the...
1311.2710v1
2013-12-12
Commissioning of the Francium Trapping Facility at TRIUMF
We report on the successful commissioning of the Francium Trapping Facility at TRIUMF. Large laser-cooled samples of francium are produced from a francium ion beam delivered by the ISAC radioactive ion beam facility. The ion beam is neutralized on an yttrium foil, which is subsequently heated to transfer the atoms into...
1312.3562v1
2014-04-11
Rotated stripe order and its competition with superconductivity in La$_{1.88}$Sr$_{0.12}$CuO$_4$
We report the observation of a bulk charge modulation in La$_{1.88}$Sr$_{0.12}$CuO$_4$ (LSCO) with a characteristic in-plane wave-vector of (0.236, $\pm \delta$), with $\delta$=0.011 r.l.u. The transverse shift of the ordering wave-vector indicates the presence of rotated charge-stripe ordering, demonstrating that the ...
1404.3193v2
2014-04-21
Wide-angle energy-momentum spectroscopy
Light emission is defined by its distribution in energy, momentum, and polarization. Here, we demonstrate a method that resolves these distributions by means of wide-angle energy-momentum spectroscopy. Specifically, we image the back focal plane of a microscope objective through a Wollaston prism to obtain polarized Fo...
1404.5109v1
2014-06-20
Photoluminescence of focused ion beam implanted Er$^{3+}$:Y$_{2}$SiO$_{5}$ crystals
Erbium doped low symmetry Y$_2$SiO$_5$ crystals attract a lot of attention in perspective of quantum information applications. However, only doping of the samples during growth is available up to now, which yields a quite homogeneous doping density. In the present work, we deposit Er$^{3+}$-ions by the focused ion beam...
1406.5371v1
2014-10-21
Radial velocity measurements of the pulsating zirconium star: LS IV -14 116
The helium-rich hot subdwarf LS IV -14 116 shows remarkably high surface abundances of zirconium, yttrium, strontium, and germanium, indicative of strong chemical stratification in the photosphere. It also shows photometric behaviour indicative of non-radial g-mode pulsations, despite having surface properties inconsis...
1410.5732v1
2015-01-09
Coherent frequency up-conversion of microwaves to the optical telecommunications band in an Er:YSO crystal
The ability to convert quantum states from microwave photons to optical photons is important for hybrid system approaches to quantum information processing. In this paper we report the up-conversion of a microwave signal into the optical telecommunications wavelength band using erbium dopants in a yttrium orthosilicate...
1501.02014v2
2015-01-20
Rotational state microwave mixing for laser cooling of complex diatomic molecules
We demonstrate the mixing of rotational states in the ground electronic state using microwave radiation to enhance optical cycling in the molecule yttrium (II) monoxide (YO). This mixing technique is used in conjunction with a frequency modulated and chirped continuous wave laser to slow longitudinally a cryogenic buff...
1501.04683v1
2015-03-17
The Hubbard model in strong magnetic field: Low-frequency quantum oscillations due to strong electron correlations
The density of states of the two-dimensional fermionic Hubbard model in the perpendicular homogeneous magnetic field is calculated using the strong coupling diagram technique. The density of states at the Fermi level as a function of the inverse magnetic induction oscillates, and the frequency of these oscillations inc...
1503.04934v1
2015-03-25
Cold Brownian motion in aqueous media via anti-Stokes photoluminescence
Advances in cryogenic sciences have enabled several observations of new low-temperature physical phenomena including superconductivity, superfluidity, and Bose-Einstein condensates. Heat transfer is also critical in numerous applications including thermal management within integrated microelectronics and the regulation...
1503.07265v1
2015-04-03
High-resolution spectroscopy of single Pr$^{3+}$ ions on the $^3$H$_4$-$^1$D$_2$ transition
Rare earth ions in crystals exhibit narrow spectral features and hyperfine-split ground states with exceptionally long coherence times. These features make them ideal platforms for quantum information processing in the solid state. Recently, we reported on the first high-resolution spectroscopy of single Pr$^{3+}$ ions...
1504.00857v1
2015-07-03
Nanophotonic coherent light-matter interfaces based on rare-earth-doped crystals
Quantum light-matter interfaces (QLMIs) connecting stationary qubits to photons will enable optical networks for quantum communications, precise global time keeping, photon switching, and studies of fundamental physics. Rare-earth-ion (REI) doped crystals are state-of-the-art materials for optical quantum memories and ...
1507.00977v1
2015-10-19
Ferroelectric polarization switching with a remarkably high activation-energy in orthorhombic GaFeO3 thin films
Orthorhombic GaFeO3 (o-GFO) with the polar Pna21 space group is a prominent ferrite by virtue of its piezoelectricity and ferrimagnetism, coupled with magneto-electric effects. Herein, we unequivocally demonstrate a large ferroelectric remanent polarization in undoped o-GFO thin films by adopting either a hexagonal str...
1510.05359v1
2015-10-29
Controlled emission and coupling of small-size YAG:Ce3+ nanocrystals to gold nanowire
We report a controlled emission of Ce3+ ions inside single Yttrium Aluminum Gar- net Y3Al5O12 (YAG:Ce3+) nanocrystals with a diameter of 22 +- 10 nm as a result of a coupling of a surface plasmon mode propagating along single gold nanowire (NW). From the PL images, the intensity for single YAG:Ce3+ nanocrystals in the ...
1510.08769v1
2015-12-11
Coupling erbium spins to a three-dimensional superconducting cavity at zero magnetic field
We experimentally demonstrate the coupling at zero magnetic field of an isotopically pure erbium doped yttrium orthosilicate crystal ($^{167}$Er:YSO) to a three-dimensional superconducting cavity with a $Q$ factor of $10^5$. A tunable loop-gap resonator is used, and its resonance frequency is tuned to observe the hyper...
1512.03606v2
2016-02-08
Phase separated behavior in Yttrium doped CaMnO3
The effect of electron doping on the structural, transport, and magnetic properties of Mn (IV) - rich Ca1-xYxMnO3 (x < 0.2) samples have been investigated using neutron diffraction, neutron depolarization, magnetization and resistivity techniques. The temperature dependence of resistivity follows the small polaron mode...
1602.02479v1
2016-07-05
Effects of intense optical phonon pumping on the structure and electronic properties of yttrium barium copper oxide
We investigate the structural modulations induced by optical excitation of a polar phonon mode in YBa$_2$Cu$_3$O$_7$, using first-principles calculations based on density functional theory. We focus on the intense-excitation regime in which we expect that fourth-order phonon-phonon coupling terms dominate, and model th...
1607.01180v2
2017-02-08
Low-Temperature Microwave Properties of Biaxial YAlO3
Low-loss crystals with defects due to paramagnetic or rare earth impurity ions is a major area of investigation for quantum hybrid systems at both optical and microwave frequencies. In this work we examine the single crystal yttrium aluminium perovskite, YAlO$_3$ using the Whispering Gallery Mode Technique. Multiple re...
1702.02288v2
2017-12-22
Magnetoresistance in YBi and LuBi semimetals due to nearly perfect carrier compensation
Monobismuthides of yttrium and lutetium are shown as new representatives of materials which exhibit extreme magnetoresistance and magnetic-field-induced resistivity plateau. At low temperatures and in magnetic field of 9T the magnetoresistance attains the order of magnitude of 10,000% and 1,000%, on YBi and LuBi, respe...
1712.08433v3
2018-03-20
Optically addressing single rare-earth ions in a nanophotonic cavity
We demonstrate optical probing of spectrally resolved single Nd rare-earth ions in yttrium orthovanadate. The ions are coupled to a photonic crystal resonator and show strong enhancement of the optical emission rate via the Purcell effect, resulting in near radiatively limited single photon emission. The measured high ...
1803.07520v2
2018-08-03
3-D Magneto-Optical Trap of Yttrium Monoxide
We report three-dimensional trapping of an oxide molecule (YO), using a radio-frequency magneto-optical trap (MOT). The total number of molecules loaded is $\sim$1.5$\times10^4$ , with a temperature of 7(1)~mK. This diversifies the frontier of molecules that are laser coolable and paves the way for the second-stage nar...
1808.01067v1
2018-08-21
Superconductivity at 215 K in lanthanum hydride at high pressures
We synthesized lanthanum hydride (LaHx) by laser heating of lanthanum in hydrogen atmosphere at pressure P = 170 GPa. The sample shows a superconducting step at 209 K and 170 GPa and temperature dependence of resistance. By releasing the pressure to 150 GPa, the superconducting transition temperature Tc increases to 21...
1808.07039v1
2018-10-06
Ultrafast negative thermal expansion driven by spin-disorder
We measure the transient strain profile in a nanoscale multilayer system composed of Yttrium, Holmium and Niobium after laser excitation using ultrafast X-ray diffraction. The strain propagation through each layer is determined by transient changes of the material-specific Bragg angles. We experimentally derive the exp...
1810.03036v1
2018-10-30
Magnetic field sensing with the kinetic inductance of a high-$T_\mathrm{c}$ superconductor
We carry out an experimental feasibility study of a magnetic field sensor based on the kinetic inductance of the high-$T_\mathrm{c}$ superconductor yttrium barium copper oxide. We pattern thin superconducting films into radio-frequency resonators that feature a magnetic field pick-up loop. At 77 K and for film thicknes...
1810.12725v1
2018-11-14
Observation of Optical Refrigeration in a Holmium-doped Crystal
We report the first demonstration of solid-state optical refrigeration of a Ho-doped material. A 1 mol% Ho-doped Yttrium Lithium Fluoride (YLF) crystal is cooled by mid-IR laser radiation, and its external quantum efficiency and parasitic background absorption are evaluated. Using detailed temperature-dependent spectro...
1811.05745v1
2018-12-05
Influence of composition and heating schedules on compatibility of FeCrAl alloys with high-temperature steam
FeCrAl alloys are proposed and being intensively investigated as alternative accident tolerant fuel (ATF) cladding for nuclear fission application. Herein, the influence of major alloy elements (Cr and Al), reactive element effect and heating schedules on the oxidation behavior of FeCrAl alloys in steam up to 1500{\deg...
1812.01850v1
2018-12-21
Deep and persistent spectral holes in Tm-doped yttrium orthosilicate for imaging applications
With their optical wavelength in the near infrared (790-800nm) and their unique spectroscopic properties at cryogenic temperatures, thulium-doped crystals are at the center of many architectures linked to classical signal processing and quantum information. In this work, we focus on Tm-doped YSO, a compound that was le...
1812.10369v2
2019-04-17
Nanophotonic quantum storage at telecommunications wavelength
Quantum memories for light are important components for future long distance quantum networks. We present on-chip quantum storage of telecommunications band light at the single photon level in an ensemble of erbium-167 ions in an yttrium orthosilicate photonic crystal nanobeam resonator. Storage times of up to 10 $\mu$...
1904.08052v1
2019-04-17
Aqueous metal-organic solutions for YSZ thin film inkjet deposition
Inkjet printing of 8% Y2O3-stabilized ZrO2 (YSZ) thin films is achieved by designing a novel water-based reactive ink for Drop-on-Demand (DoD) inkjet printing. The ink formulation is based on a novel chemical strategy that consists of a combination of metal oxide precursors (zirconium alkoxide and yttrium salt), water ...
1904.08143v1
2019-07-28
Coherent control and single-shot readout of a rare-earth ion embedded in a nanophotonic cavity
Quantum networks based on optically addressable spin qubits promise to enable secure communication, distributed quantum computing, and tests of fundamental physics. Scaling up quantum networks based on solid-state luminescent centers requires coherent spin and optical transitions coupled to photonic resonators. Here we...
1907.12161v1
2019-08-18
Pressure induced electronic structure transformation of topological semimetal
We study the electronic structure change of yttrium trihydride $\mathrm{YH_3}$ by applying a hydrostatic pressure. At zero pressure, $\mathrm{YH_3}$ has the structure with energy favored symmetry group $P\bar{3}c1$ (165). From first principle calculation, we argue that the band crossings are caused by overlapping of an...
1908.06494v2
2019-08-28
Alkali ion-to-neutral atom converter for the magneto-optical trap of a radioactive isotope
We have developed a unique neutralizer device that uses an yttrium target surrounded by a platinum wall to magneto-optically trap radioactive atoms. In general, the radioactive nucleus produced in a nuclear reaction is extracted and transported in ion form. For the magneto-optical trap, thermal neutralization must occu...
1908.10686v1
2019-09-26
Coherent charge and magnetic ordering in Ho/Y superlattice revealed by element-selective x-ray scattering
Magnetic rare-earth / non-magnetic metal superlattices are well-known to display chiral spin helices in the rare-earth layers that propagate coherently across the non-magnetic layers. However, the underlying mechanism that preserves the magnetic phase and chirality coherence across the non-magnetic layers has remained ...
1909.12372v2
2019-10-04
Solid-state laser refrigeration of a semiconductor optomechanical resonator
Photothermal heating represents a major constraint that limits the performance of many nanoscale optoelectronic and optomechanical devices including nanolasers, quantum optomechanical resonators, and integrated photonic circuits. Although radiation-pressure damping has been reported to cool an individual vibrational mo...
1910.02153v1
2019-10-20
A search for heavy-metal stars: abundance analyses of hot subdwarfs with Subaru
The discovery of extremely zirconium- and lead-rich surfaces amongst a small subgroup of hot subdwarfs has provoked questions pertaining to chemical peculiarity in hot star atmospheres and about their evolutionary origin. With only three known in 2014, a limited search for additional `heavy-metal' subdwarfs was initiat...
1910.08947v1
2019-10-31
Optically unstable phase from ion-ion interactions in an erbium doped crystal
We demonstrate an optical unstable phase for a laser driven erbium ion ensemble. The transmitted light through an erbium-doped yttrium orthosillicate crystal becomes dynamically unstable when illuminated by a strong continuous-wave laser. Transient net gain was recorded if the light passes the sample twice. The experim...
1910.14298v2
2019-12-08
On-chip coherent microwave-to-optical transduction mediated by ytterbium in YVO$_4$
Optical networks that distribute entanglement among quantum technologies will form a powerful backbone for quantum science but are yet to interface with leading quantum hardware such as superconducting qubits. Consequently, these systems remain isolated because microwave links at room temperature are noisy and lossy. B...
1912.03671v1
2019-12-16
The nature of the photometric variability of HgMn stars: A test of simulated light curves of φ Phe against the TESS data
The inhomogeneous surface distribution of heavy elements is known to cause periodic light variability of magnetic chemically peculiar stars. It is unclear to what extent the same paradigm applies to mercury-manganese (HgMn) stars. We aim to model the photometric variability of the HgMn star {\phi}Phe using abundance ma...
1912.07265v1
2020-01-15
Stability and superconductivity of lanthanum and yttrium decahydrides
Rare-earth hydrides can exhibit high-temperature superconductivity under high pressure. Here, we apply a crystal structure prediction method to the current record-holding $T_c$ material, LaH$_{10}$, and a candidate for even higher $T_c$, YH$_{10}$. We find a pressure-induced phase transition from the experimentally obs...
2001.05305v3
2020-01-31
Sub-Doppler Cooling and Compressed Trapping of YO Molecules at $μ$K Temperatures
Complex molecular structure demands customized solutions to laser cooling by extending its general set of principles and practices. Yttrium monoxide (YO) has unique intramolecular interactions. The Fermi-contact interaction dominates over the spin-rotation coupling, resulting in two manifolds of closely spaced states, ...
2002.00056v1
2020-05-27
Demonstration of site-selective angular-resolved absorption spectroscopy of the $^{4}I_{15/2} \rightarrow $$^{4}I_{13/2}$ erbium transition in the monoclinic crystal Y$_2$SiO$_5$
We study the angular dependence in polarized light of the optical absorption for the Er$^{3+}$ transition $^{4}I_{15/2} \rightarrow $$^{4}I_{13/2}$ in Y$_2$SiO$_5$, revealing thus the associated anisotropy and the orientation of the related absorption principal directions in the dielectric plan perpendicular to the mon...
2005.13626v2
2020-08-25
Multifunctional on-chip storage at telecommunication wavelength for quantum networks
Quantum networks will enable a variety of applications, from secure communication and precision measurements to distributed quantum computing. Storing photonic qubits and controlling their frequency, bandwidth and retrieval time are important functionalities in future optical quantum networks. Here we demonstrate these...
2008.10795v1
2020-09-02
Peculiarities of Abundances of Selected Elements in Metal-Rich Field RR Lyrae Stars
We use the data of our extended catalog of spectroscopic determinations of elemental abundances in the atmospheres of Galactic-field RR Lyrae type variables to show that metal-rich RR Lyraes ($\rm{[Fe/H]} > -1.0$) have anomalous abundances of some elements. In particular, the relative abundances of scandium, titanium, ...
2009.00906v1
2020-09-29
Distal edge determination precision for a multi-slat promptgamma camera: a comprehensive simulation and optimization of the detection system
Multi-slat prompt-gamma camera is a promising tool for range monitoring during proton therapy. We report the results of a comprehensive simulation study analyzing the precision which is possible to reach with this camera in determination of the position of the distal edge of the Bragg peak. For the first time we includ...
2009.14154v2
2020-11-03
Strongly correlated bistable sublattice and temperature hysteresis of elastic and thermal crystal properties
It is shown that in crystal lattices with a basis the cooperative behavior of a certain type of atoms performing optical long-wavelength vibrations in a double-well potential of the field of the matrix lattice may lead to the formation of a bistable sublattice. As a result of the interaction of the metastable states of...
2011.01594v1
2020-12-11
Local-mean preserving post-processing step for non-negativity enforcement in PET imaging: application to $^{90}$Y-PET
In a low-statistics PET imaging context, the positive bias in regions of low activity is a burning issue. To overcome this problem, algorithms without the built-in non-negativity constraint may be used. They allow negative voxels in the image to reduce, or even to cancel the bias. However, such algorithms increase the ...
2012.06432v1
2021-02-03
Evolutionary search for cobalt-rich compounds in the yttrium-cobalt-boron system
Modern high-performance permanent magnets are made from alloys of rare earth and transition metal elements, and large magnetization is achieved in the alloys with high concentration of transition metals. We applied evolutionary search scheme based on first-principles calculations to the Y-Co-B system and predicted 37 c...
2102.02097v1
2021-04-03
Characterization of Er$^{3+}$:YVO$_{4}$ for microwave to optical transduction
Quantum transduction between microwave and optical frequencies is important for connecting superconducting quantum platforms in a quantum network. Ensembles of rare-earth ions are promising candidates to achieve this conversion due to their collective coherent properties at microwave and optical frequencies. Erbium ion...
2104.01501v1
2021-04-09
Polarons formation in Bi-deficient BaBiO$_3$
BaBiO$_3$ is a charged ordered Peierls-like perovskite well known for its superconducting properties upon K or Pb doping. We present a study on the transport and electronic properties of BaBiO$_3$ perovskite with strong Bi-deficiency. We show that it is possible to synthesize BaBiO$_3$ thin layers with Bi-vacancies abo...
2104.04573v1
2021-05-12
Probing Strong Coupling between a Microwave Cavity and a Spin Ensemble with Raman Heterodyne Spectroscopy
Raman heterodyne spectroscopy is a powerful tool for characterizing the energy and dynamics of spins. The technique uses an optical pump to transfer coherence from a spin transition to an optical transition where the coherent emission is more easily detected. Here Raman heterodyne spectroscopy is used to probe an iso...
2105.05387v1
2021-06-06
Prediction of half-metallicity and spin-gapless semiconducting behavior in the new series of FeCr-based quaternary Heusler alloys: an ab initio study
This paper presents a detailed investigation of FeCr-based quaternary Heusler alloys. By using ultrasoft pseudopotential, electronic and magnetic properties of the compounds are studied within the framework of Density Functional Theory (DFT) by using the Quantum Espresso package. The thermodynamic, mechanical, and dyna...
2106.03026v1
2021-07-13
High Phase-Space Density of Laser-Cooled Molecules in an Optical Lattice
We report laser cooling and trapping of yttrium monoxide (YO) molecules in an optical lattice. We show that gray molasses cooling remains exceptionally efficient for YO molecules inside the lattice with a molecule temperature as low as 6.1(6) $\mu$K. This approach has produced a trapped sample of 1200 molecules, with a...
2107.06422v2
2021-08-11
Optical excitation and probing of the antiferromagnetic modes with non-uniform in-depth distribution in birefringent antiferromagnetic crystals
Optical pump-probe setups are commonly used for excitation and investigation of the spin dynamics in various types of magnetic materials. However, usually the spatially homogeneous excitation is considered. In the present study we describe an approach for optical excitation of the nonuniform THz spin dynamics and for p...
2108.05443v2
2022-01-29
Vibrational fingerprints of ferroelectric hafnia
Hafnia (HfO2) is a promising material for emerging chip applications due to its high-k dielectric behaviour, suitability for negative capacitance heterostructures, scalable ferroelectricity, and silicon compatibility. The lattice dynamics along with phononic properties such as thermal conductivity, contraction, and hea...
2201.12643v1
2022-06-22
An improved smart meta-superconductor MgB2
Increasing and improving the critical transition temperature (Tc), current density (Jc) and Meissner effect (Hc) of conventional superconductors are the most important problems in superconductivity research, but progress has been slow for many years. In this study, by introducing the p-n junction electroluminescent inh...
2206.10940v1
2022-07-05
Proposal for spin squeezing in rare-earth ion-doped crystals with a four-color scheme
Achieving spin squeezing within solid-state devices is a long standing research goal, due to the promise of their particularities, for instance their long coherence times, the possibility of low-temperature experiments or integration of entanglement-assisted sensors on-chip. In this work, we investigate an interferomet...
2207.02169v2
2022-08-22
Magnetically Tuned Continuous Transition from Weak to Strong Coupling in Terahertz Magnon Polaritons
Depending on the relative rates of coupling and dissipation, a light-matter coupled system is either in the weak- or strong-coupling regime. Here, we present a unique system where the coupling rate continuously increases with an externally applied magnetic field while the dissipation rate remains constant, allowing us ...
2208.10030v1
2022-08-29
Frequency Response Analysis of Backside Illuminated Free-Membrane Type IR Superconducting Bolometer
The IR response of a backside illuminated type Yttrium Barium Copper Oxide (YBCO) transition-edge bolometer (TEB) in a free-membrane configuration is measured and analyzed. The analysis is based on a comprehensive equivalent circuit model for the bolometer structure considering all the thermal parameters of the device....
2208.13711v1
2022-10-08
Valence and magnetism in $\rm EuPd_3S_4$ and $\rm (Y,La)_xEu_{1-x}Pd_3S_4$
$^{151}$Eu M\"ossbauer spectroscopy shows that yttrium substitution in mixed-valent $\rm EuPd_3S_4$ drives the initial 50:50 mix of Eu$^{3+}$ and Eu$^{2+}$ towards pure Eu$^{2+}$, whereas lanthanum substitution has the opposite effect, but only for substitution levels above 50\%. We find that total valence electron cou...
2210.03860v1
2022-11-04
In-plane anisotropy of electrical transport in Y$_{0.85}$Tb$_{0.15}$Ba$_2$Cu$_3$O$_{7-x}$ films
We fabricate high-quality c-axis oriented epitaxial YBa$_2$Cu$_3$O$_{7-x}$ films with 15% of yttrium atoms replaced by terbium (YTBCO) and study their electrical properties. The Tb substitution reduces the charge carrier density resulting in increased resistivity and decreased critical current density compared to the p...
2211.02564v2
2022-12-03
Microstructure Evolution of Solid Oxide Fuel Cell Anodes Characterized by Persistent Homology
Uncovering microstructure evolution mechanisms that accompany the long-term operation of solid oxide fuel cells is a fundamental challenge in designing a more durable energy system for the future. To date, the study of fuel cell stack degradation has focused mainly on electrochemical performance and, more rarely, on av...
2212.01576v1
2023-02-02
Superconducting phases of YH9 under pressure
Yttrium superhydrides has attracted much attention due to their multiple stoichiometries and excellent superconductivities under high pressure. Especially, YH9 have a Tc of 243 K, which is the second highest Tc among all binary hydrides. It exhibits a positive pressure dependence of Tc below 200 GPa, contrary to the re...
2302.01122v2
2023-06-26
Discovery of a 760 nm P Cygni line in AT2017gfo: Identification of yttrium in the kilonova photosphere
Neutron star mergers are believed to be a major cosmological source of rapid neutron-capture elements. The kilonovae associated with neutron star mergers have to date yielded only a single well-identified spectral signature: the P Cygni line of Sr$^+$ at about 1$\mu$m in the spectra of the optical transient, AT2017gfo....
2306.14942v1
2023-09-25
Simultaneous High-Speed and Low-Dose 4-D STEM Using Compressive Sensing Techniques
Here we show that compressive sensing allow 4-dimensional (4-D) STEM data to be obtained and accurately reconstructed with both high-speed and low fluence. The methodology needed to achieve these results compared to conventional 4-D approaches requires only that a random subset of probe locations is acquired from the t...
2309.14055v3
2023-10-10
Optical assembly of nanostructures mediated by surface roughness
Rigorous understanding of the self-assembly of colloidal nanocrystals is crucial to the development of tailored nanostructured materials. Despite extensive studies, a mechanistic understanding of self-assembly under non-equilibrium driven by an external field remains an ongoing challenge. We demonstrate self-assembly b...
2310.06774v1
2023-11-28
Spectral Multiplexing of Rare-earth Emitters in a Co-doped Crystalline Membrane
The spectral addressing of many individual rare-earth dopants in optical resonators offers great potential for realizing distributed quantum information processors. To this end, it is required to understand and control the spectral properties of the emitters in micron-scale devices. Here, erbium emitters are investigat...
2311.16875v2
2024-01-21
Levitodynamic spectroscopy for single nanoparticle characterisation
Fast detection and characterization of single nanoparticles such as viruses, airborne aerosols and colloidal particles are considered to be particularly important for medical applications, material science and atmospheric physics. In particular, non-intrusive optical characterization, which can be carried out in isolat...
2401.11551v1
2024-02-04
High temperature deformation mechanisms in monolithic 3YTZP and 3YTZP containing single wall carbon nanotubes
Monolithic 3YTZP and 3YTZP containing 2.5 vol.% of single-walled carbon nanotubes (SWCNT) were fabricated by Spark Plasma Sintering (SPS) at 1250 C. Microstructural characterization of the as-fabricated 3YTZP/SWCNTs composite shows a homogeneous CNTs dispersion throughout of ceramic matrix. The specimens have been crep...
2402.06651v1
1998-04-06
Detection of an iron K Emission Line from the LINER NGC 4579
We present the results of an ASCA observation of the LINER NGC 4579. A point-like X-ray source is detected at the nucleus with a 2-10 keV luminosity of 1.5x10^41 ergs/s assuming a distance of 16.8 Mpc. The X-ray spectrum is represented by a combination of a power-law with a photon index of ~1.7 and soft thermal compone...
9804054v1
1998-10-01
Compton reflection and iron fluorescence in AGN and GBHCs
Any cold, optically-thick matter in the vicinity of an accreting black hole, such as the accretion disk, can intercept and reprocess some fraction of the hard X-ray continuum emission, thereby imprinting atomic features into the observed spectrum. This process of `X-ray reflection' primarily gives rise to a broad refle...
9810018v1
2000-10-24
XMM-Newton observation of an unusual iron line in the quasar Markarian 205
XMM-Newton observations of the low luminosity, radio-quiet quasar Markarian 205 have revealed a unique iron K emission line profile. In marked contrast to the broad and redshifted iron K line commonly seen in ASCA observations of Seyfert 1 galaxies, we find that a substantial amount of the line flux in Mrk 205 occurs a...
0010490v1
2001-11-02
Spectroscopic Signatures of Convection in the Spectrum of Procyon. Fundamental Parameters and Iron Abundance
We have observed the spectrum of Procyon A (F5IV) from 4559 to 5780 A with a S/N of ~ 1e3 and a resolving power of 2e5. We have measured the line bisectors and relative line shifts of a large number of Fe I and Fe II lines, comparing them to those found in the Sun. A three-dimensional(3D) hydrodynamical model atmospher...
0111055v1
2002-01-09
Dust and the spectral energy distribution of the OH/IR star OH 127.8+0.0: Evidence for circumstellar metallic iron
We present a fit to the spectral energy distribution of OH 127.8+0.0, a typical asymptotic giant branch star with an optically thick circumstellar dust shell. The fit to the dust spectrum is achieved using non-spherical grains consisting of metallic iron, amorphous and crystalline silicates and water ice. Previous simi...
0201128v1
2002-04-09
Short Timescale Correlations Between Line and Continuum Fluxes in Cygnus X-1
We present the results of 16-s time scale spectral fits for Cygnus X-1 in the soft state and in the transition state, using a Comptonised blackbody plus an iron line. On these timescales, we find that that the continuum source flux can vary by factors 2-3 and that the iron line intensity appears to track these changes ...
0204160v2
2002-10-11
Iron abundances and heating of the ICM in hydrodynamical simulations of galaxy clusters
Results from a large set of hydrodynamical SPH simulations of galaxy clusters in a flat LCDM cosmology are used to investigate the metal enrichment and heating of the ICM. The physical modeling of the gas includes radiative cooling, star formation, energy feedback and metal enrichment that follow from the explosions of...
0210263v2
2003-07-12
Early star formation traced by the highest redshift quasars
The iron abundance relative to alpha-elements in the circumnuclear region of quasars is regarded as a clock of the star formation history and, more specifically, of the enrichment by SNIa. We investigate the iron abundance in a sample of 22 quasars in the redshift range 3.0<z<6.4 by measuring their rest frame UV FeII b...
0307264v2
2003-07-16
Abundance Analysis of Planetary Host Stars I. Differential Iron Abundances
We present atmospheric parameters and iron abundances derived from high-resolution spectra for three samples of dwarf stars: stars which are known to host close-in giant planets (CGP), stars for which radial velocity data exclude the presence of a close-in giant planetary companion (no-CGP), as well as a random sample ...
0307321v1
2004-02-06
A Two-Dimensional Hydrostatically Equilibrium Atmosphere of a Neutron Star with Given Differential Rotation
An analytic solution has been found in the Roche approximation for the axially symmetric structure of a hydrostatically equilibrium atmosphere of a neutron star produced by collapse. A hydrodynamic (quasione-dimensional) model for the collapse of a rotating iron core in a massive star gives rise to a heterogeneous rota...
0402151v1
2005-04-25
A New Model for Iron Emission Lines and Re-Burst in GRB X-Ray Afterglows
Recently iron emission features have been observed in several X-ray afterglows of GRBs. It is found that the energy obtained from the illuminating continuum which produces the emission lines is much higher than that of the main burst.The observation of SN-GRB association indicates a fallback disk should be formed after...
0504533v2
2006-05-26
High-Resolution X-ray Spectroscopy of the Interstellar Medium II: Neon and Iron Absorption Edges
We present high-resolution spectroscopy of the neon K-shell and iron L-shell interstellar absorption edges in nine X-ray binaries using the High Energy Transmission Grating Spectrometer (HETGS) onboard the Chandra X-ray Observatory. We found that the iron absorption is well fit by an experimental determination of the c...
0605674v1
2007-06-21
The nature of the fluorescent iron line in V 1486 Ori
The fluorescent 6.4 keV iron line provides information on cool material in the vicinity of hard X-ray sources as well as on the characteristics of the X-ray sources themselves. First discovered in the X-ray spectra of the flaring Sun, X-ray binaries and active galactic nuclei (AGN), the fluorescent line was also observ...
0706.3097v1
2007-10-04
New Insights on Interstellar Gas-Phase Iron
In this paper, we report on the gas-phase abundance of singly-ionized iron (Fe II) for 51 lines of sight, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE). Fe II column densities are derived by measuring the equivalent widths of several ultraviolet absorption lines and subsequently fitting those to a c...
0710.1062v1
2008-06-20
Bandwidth and Fermi surface of Iron-Oxypnictides: covalency and sensitivity to structural changes
Some important aspects of the electronic structure of the iron oxypnictides depend very sensitively on small changes in interatomic distances and bond angles within the iron-pnictogen subunit. Using first-principles full-potential electronic structure calculations, we investigate this sensitive dependence, contrasting ...
0806.3285v1
2008-07-24
The Unprecedented Giant Coupling of Fe-spin State and the As-As Hybridization in Iron-Pnictide
From first principles calculations we unravel surprisingly strong interactions between arsenic ions in iron-pnictides, the strength of which is controlled by the Fe-spin state. Reducing the Fe-magnetic moment, weakens the Fe-As bonding, and in turn, increases As-As interactions, causing giant reduction in the c-axis. F...
0807.3936v3
2008-12-12
Experimental determination of the microscopic origin of magnetism in parent iron pnictides
Like high Tc cuprates, the newly discovered iron based superconductors lie in close proximity to a magnetically ordered parent phase. However, while the magnetic order in parent cuprates is known to derive from a spin-spin local superexchange interaction, a plethora of experiments including neutron scattering have so f...
0812.2289v1
2009-01-27
Correlation effects in the iron pnictides
One of the central questions about the iron pnictides concerns the extent to which their electrons are strongly correlated. Here we address this issue through the phenomenology of the charge transport and dynamics, single-electron excitation spectrum, and magnetic ordering and dynamics. We outline the evidence that the...
0901.4112v2
2010-09-14
Comment on "Isotope effect in multi-band and multi-channel attractive systems and inverse isotope effect in iron-based superconductors" by T. Yanagisawa, et al
In a recent paper Yanagisawa et al. [1] claim from a theoretical analysis of a multi-channel multi-band superconductor model that an inverse isotope exponent on the superconducting transition temperature Tc can be realized in iron-based superconductors. Simultaneously, a subgroup of the authors of Ref. 1 performed the ...
1009.2590v1
2010-12-23
Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
Up to now, there have been two material families, the cuprates and the iron-based compounds with high-temperature superconductivity (HTSC). An essential open question is whether the two classes of materials share the same essential physics. In both, superconductivity (SC) emerges when an antiferromagnetical (AFM) order...
1012.5236v1
2011-01-17
Modeling the iron oxides and oxyhydroxides for the prediction of environmentally sensitive phase transformations
Iron oxides and oxyhydroxides are challenging to model computationally as competing phases may differ in formation energies by only several kJ/mol, they undergo magnetization transitions with temperature, their structures may contain partially occupied sites or long-range ordering of vacancies, and some loose structure...
1101.3105v1
2011-08-03
Origin of conductivity cross over in entangled multi-walled carbon nanotube network filled by iron
A realistic transport model showing the interplay of the hopping transport between the outer shells of iron filled entangled multi-walled carbon nanotubes (MWNT) and the diffusive transport through the inner part of the tubes, as a function of the filling percentage, is developed. This model is based on low-temperature...
1108.0881v1
2011-10-17
Testing the sign-changing superconducting gap in iron-based superconductors with quasiparticle interference and neutron scattering
We present a phenomenological calculation of the quasiparticle-interference (QPI) pattern and inelastic Neutron scattering (INS) spectra in iron-pnictide and layered iron-selenide compounds by using materials specific band-structure and superconducting (SC) gap properties. As both the QPI and the INS spectra arise due ...
1110.3834v2
2012-02-27
$S_4$ Symmetric Microscopic Model for Iron-Based Superconductors
Although iron-based superconductors are multi-orbital systems with complicated band structures, we demonstrate that the low energy physics which is responsible for high-$T_c$ superconductivity is essentially governed by one effective Hamiltonianwith two almost decoupled orbitals near half filling. This underlining elec...
1202.5881v5
2012-04-24
Microstructural analysis of phase separation in iron chalcogenide superconductors
The interplay between superconductivity, magnetism and crystal structure in iron-based superconductors is a topic of great interest amongst the condensed matter physics community as it is thought to be the key to understanding the mechanisms responsible for high temperature superconductivity. Alkali metal doped iron ch...
1204.5472v4
2012-04-25
A Monte Carlo Markov Chain based investigation of black hole spin in the active galaxy NGC3783
The analysis of relativistically broadened X-ray spectral features from the inner accretion disk provides a powerful tool for measuring the spin of supermassive black holes (SMBH) in active galactic nuclei (AGN). However, AGN spectra are often complex and careful analysis employing appropriate and self-consistent model...
1204.5747v2
2012-09-19
Orbital and spin magnetic moments of transforming 1D iron inside metallic and semiconducting carbon nanotubes
The orbital and spin magnetic properties of iron inside transforming metallic and semiconducting 1D carbon nanotube hybrids are studied by means of local x-ray magnetic circular dichroism (XMCD) and bulk superconducting quantum interference device (SQUID) measurements. Nanotube hybrids are initially ferrocene filled si...
1209.4265v1
2013-03-12
Démixtion et ségrégation superficielle dans les alliages fer-chrome
Ferritic steels possibly strengthened by oxide dispersion are candidates as structural materials for generation IV and fusion nuclear reactors. Their use is limited by incomplete knowledge of the iron-chromium phase diagram at low temperatures and of the phenomena inducing preferential segregation of one element at gra...
1303.2938v1
2013-03-29
A magnetic origin for high temperature superconductivity in iron pnictides
In conventional Bardeen-Cooper-Schrieffer (BCS) superconductors, superconductivity occurs when electrons form coherent Cooper pairs below the superconducting transition temperature Tc. Although the kinetic energy of paired electrons increases in the superconducting state relative to the normal state, the reduction in t...
1303.7339v1
2013-05-03
Photophoretic separation of metals and silicates: the formation of Mercury like planets and metal depletion in chondrites
Mercury's high uncompressed mass density suggests that the planet is largely composed of iron, either bound within metal (mainly Fe-Ni), or iron sulfide. Recent results from the MESSENGER mission to Mercury imply a low temperature history of the planet which questions the standard formation models of impact mantle stri...
1305.0689v1
2013-07-03
Galactic Constraints on Supernova Progenitor Models
We undertake a statistical analysis of the radial abundance distributions in the Galactic disk within a theoretical framework for Galactic chemical evolution which incorporates the influence of spiral arms. 1) The mean mass of oxygen ejected per core-collapse SNe (CC SNe) event (which are concentrated within spiral arm...
1307.0928v1