jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Richard Hess | Henry F. Legg | Daniel Loss | Jelena Klinovaja
Source: arXiv (Cornell University) (preprint, 2023-08-09)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Josephson transistor from the superconducting diode effect in domain wall and skyrmion magnetic racetracks In superconductors, the combination of broken time-reversal and broken inversion symmetries can result in a critical current being dependent on the direction of current flow. This phenomenon is known as superconducting diode effect (SDE) and has great potential for applications in future low-temperature electronics. Here, we investigate how magnetic textures such as domain walls or skyrmions on a racetrack can be used to control the SDE in a Josephson junction and how the SDE can be used as a low-temperature read-out of the data in racetrack memory devices. First, we consider a two-dimensional electron gas (2DEG) with strong spin-orbit-interaction (SOI) coupled to a magnetic racetrack, which forms the weak-link in a Josephson junction. In this setup, the exchange coupling between the magnetic texture and the itinerant electrons in the 2DEG breaks time-reversal symmetry and enables the SDE. When a magnetic texture, such as a domain wall or skyrmion enters the Josephson junction, the local exchange field within the junction is changed and, consequently, the strength of the SDE is altered. In particular, depending on the position and form of the magnetic texture, moving the magnetic texture can cause the SDE coefficient to change its sign, enabling a Josephson transistor effect with potentially fast switching frequencies. Further, we find that the SDE is enhanced if the junction length-scales are comparable with the length-scale of the magnetic texture. Furthermore, we show that, under certain circumstances, the symmetry breaking provided by particular magnetic textures, such as skyrmions, can lead to an SDE even in the absence of Rashba SOI in the 2DEG. Our results provide a basis for new forms of readout in low-temperature memory devices as well as demonstrating how a Josephson transistor effect can be achieved even in the absence of an external magnetic field and intrinsic Rashba SOI. Condensed matter physics ; Josephson effect ; Skyrmion ; Physics ; Pi Josephson junction ; Texture (cosmology) ; Superconductivity ; Magnetic field ; Magnetic domain ; Magnetization ; Quantum mechanics Magnetic and transport properties of perovskites and related materials ; Physics of Superconductivity and Magnetism ; Electronic and Structural Properties of Oxides
Authors: Sathya Perera | Lichang Wang
Source: ChemRxiv (preprint, 2023-07-12)
Field: Materials Science — Electronic, Optical and Magnetic Materials

DFT Studies of Solvent Effect on the Strongly Coupled Vibrations of 4-Azidoacetanilide DFT calculations were performed to study the solvent effect on the vibrations of 4-azidoacetanilde in the range including the azido asymmetric stretch, i.e. 2000-2300 cm-1, using N, N-dimethylacetamide (NNDMA) and tetrahydrofuran (THF) as solvents. B3LYP functional was employed in the DFT calculations with 7 basis sets, 6-31G(d,p), 6-31+G(d,p), 6-31++G(d,p), 6-311G(d,p), 6-311+G(d,p), 6-311++G(d,p), and 6-311++G(df,pd). The results show that there are 7 combination bands coupling with the azide asymmetric stretch mode. As a result, the absorption profile of 4-azidoacetanilde is very solvent dependent. Specifically, stronger couplings of vibrations of 4-azidoacetanilde are predicted in NNDMA and the intensity of the azide asymmetric stretch is substantially reduced. Interestingly, the frequency of the azide asymmetric stretch of 4-azidoacetanilde in NNDMA is essentially the same as that of 4-azidotoulene. The intensity of the azide asymmetric stretch of 4-azidoacetanilde in THF is slightly increased with respect to that of 4-azidotoulene. Furthermore, the azide asymmetric stretch of 4-azidoacetanilde in THF remains nearly the same as in NNDMA but is blue shifted with respect to that of 4-azidotoulene. This indicates that a more complex and sensitive absorption profile will be expected when 4-azidoacetanilde is used as IR probe. Azide ; Chemistry ; Tetrahydrofuran ; Dimethylacetamide ; Solvent ; Absorption (acoustics) ; Absorption spectroscopy ; Solvent effects ; Density functional theory ; Crystallography ; Photochemistry ; Computational chemistry ; Materials science ; Organic chemistry ; Optics ; Physics Nonlinear Optical Materials Research ; Chemical Reactions and Mechanisms ; Photochemistry and Electron Transfer Studies
Authors: Ko-Fan Huang | Önder Gül | Takashi Taniguchi | Kenji Watanabe | Philip Kim
Source: Low Temperature Physics (article, 2023-06-01)
Field: Materials Science — Materials Chemistry

Andreev reflection between aluminum and graphene across van der Waals barriers We present planar aluminum superconductor–graphene junctions whose hybrid interface is engineered for couplings ranging from tunneling to the strongly coupled regime by employing an atomically thin van der Waals tunneling barrier. Without the vdW barrier, we find Al makes strongly coupled contacts with the fully proximities graphene channel underneath. Using a large band gap hexagonal boron nitride (hBN) barrier, we find the junctions always remain in the weak coupling regime, exhibiting tunneling characteristics. Using monolayer semi-conducting transition metal dichalcogenides (TMDs) such as MoS2, we realize intermediate coupling with enhanced junction conductance due to the Andreev process. In this intermediate regime, we find that junction resistance changes in discrete steps when sweeping a perpendicular magnetic field. The period of the resistance steps in the magnetic field is inversely proportional to the junction area, suggesting the physical origin of our observations is due to magnetic-field-induced vortex formation in the planar junction. Condensed matter physics ; Graphene ; Quantum tunnelling ; Andreev reflection ; Materials science ; van der Waals force ; Superconductivity ; Monolayer ; Magnetic field ; Coupling (piping) ; Planar ; Conductance ; Nanotechnology ; Physics Graphene research and applications ; Quantum and electron transport phenomena ; 2D Materials and Applications
Authors: Matteo Crispino | Pablo Villar Arribi | Anmol Shukla | F. Hardy | Amir A. Haghighirad | Thomas Wolf | R. Heid | C. Meingast | Tommaso Gorni | Adolfo Avella | Luca de’ Medici
Source: arXiv (Cornell University) (preprint, 2023-12-11)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Paradigm for finding d-electron heavy fermions: the case of Cr-doped CsFe$_2$As$_2$ We define a general strategy for finding new heavy-fermionic materials without rare-earth elements: doping a Hund metal with pronounced orbital-selective correlations towards half-filling. We argue that in general band structures a possible orbital-selective Mott transition is frustrated by inter-orbital hopping into heavy-fermion behaviour - where d-orbitals provide both the heavy and the light electrons - which is enhanced when approaching half-filling. This phase ultimately disappears due to magnetic correlations, as in a standard Doniach diagram. Experimentally we have further hole doped CsFe$_2$As$_2$, a Hund metal with 0.5 electrons/Fe away from half-filling, and obtained a heavy fermionic state with the highest Sommerfeld coefficient for Fe-pnictides to date (270 mJ/mol K$^2$), before signatures of an antiferromagnetic phase set in. Antiferromagnetism ; Condensed matter physics ; Electron ; Physics ; Heavy fermion ; Phase diagram ; Atomic orbital ; Fermion ; Doping ; Superconductivity ; Strongly correlated material ; Mott transition ; Phase (matter) ; Hubbard model ; Quantum mechanics Iron-based superconductors research ; Rare-earth and actinide compounds
Authors: Payal Wadhwa | Andrea Bosin | Alessio Filippetti
Source: Materials Horizons (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

Ultra-thin magnetic film with giant phonon-drag for heat to spin current conversion A tightly confined 2D electron gas with good carrier mobility and large spin-polarization is an essential ingredient for the implementation of spin-caloritronic conversion device technology. Here we give evidence that the SrTiO<sub>3</sub>/EuTiO<sub>3</sub>/LaAlO<sub>3</sub> heterostructure is a prototype material for this purpose. The presence of Eu induces strong spin-polarization in the 2D electron gas spontaneously formed at the interface and ferromagnetic order at low temperature. Furthermore, tight 2D confinement and spin-polarization can be highly enhanced upon charge depletion, in turn generating huge thermopower associated with the phonon-drag mechanism. Most importantly, the remarkable difference in the population of the two spin channels results in the giant spin-polarized Seebeck effect and in turn, giant spin voltages of mV K<sup>-1</sup> order at the two ends of an applied thermal gradient. Our results represent a strong assessment to the capabilities of this interface for low-temperature spin-caloritronic applications. Condensed matter physics ; Spin polarization ; Materials science ; Heterojunction ; Thermoelectric effect ; Spintronics ; Ferromagnetism ; Temperature gradient ; Drag ; Thin film ; Spin (aerodynamics) ; Charge carrier ; Electron ; Optoelectronics ; Nanotechnology ; Physics Electronic and Structural Properties of Oxides ; Magnetic and transport properties of perovskites and related materials ; Advanced Condensed Matter Physics
Authors: Dongyang Xiao | Leimeng Sun | Huanhuan Du | Xiaochen Suo | Yurong Wang | Yili Zhang | Shuangyang Kuang | Peiyi Song
Source: Research Square (preprint, 2023-06-12)
Field: Materials Science — Materials Chemistry

Boosting the Electron Beam Transmittance of Field Emission Cathode Using a Self-Charging Gate Abstract The gate-type carbon nanotubes (CNTs) cathodes exhibit advantages in long-term stable emission owing to the uniformity of electrical field on the CNTs, but the gate inevitably reduces the transmittance of electron beam (E-beam), posing challenges for system stabilities. In this work, we introduce an E-beam focusing technique using the self-charging SiNx/Au/Si gate. The surface potential of SiNx is measured to be approximately -60 V quickly after the cathode turning-on, the negative potential can be maintained as the emission goes on. The charged surface generates rebounding electrostatic forces on the following electrons, significantly focusing the E-beam on the center of gate hole and allowing them to pass through with minimal interceptions. An average transmittance of 96.17% is observed during a 550-hour prototype test. We believe that this high-efficiency, long-term stable cathode has great potential for using in neutralizers, solar sails and tethered satellites in the long-term space missions. Cathode ; Transmittance ; Materials science ; Cathode ray ; Optoelectronics ; Electron ; Field electron emission ; Electron gun ; Beam (structure) ; Carbon nanotube ; Optics ; Nanotechnology ; Electrical engineering ; Physics ; Engineering Carbon Nanotubes in Composites ; Electrohydrodynamics and Fluid Dynamics ; Advanced Electron Microscopy Techniques and Applications
Authors: Vinayakam Kalaivani | Upendra Kumar Kagola | P. V. Rajeswari | S. Kaleemulla | R. Praveena | Navoori Vijaya
Source: Luminescence (article, 2023-11-28)
Field: Materials Science — Materials Chemistry

Pure red upconverted and near‐infrared luminescence properties of Er<sup>3+</sup>‐doped SnO<sub>2</sub> nanocrystals for lighting applications Tin oxide (SnO<sub>2</sub> ) nanocrystalline powders doped with erbium ion (Er<sup>3+</sup> ) in different molar ratios (0, 3, 5, and 7 mol%) were prepared using a solid-state reaction technique. These samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible absorption, visible upconversion, and near-infrared luminescence techniques. XRD analysis revealed the tetragonal rutile structure of SnO<sub>2</sub> and the average crystallite size was about 32 nm. From Tauc's plots, it was confirmed that the substitution of Er<sup>3+</sup> ions into the SnO<sub>2</sub> host lattice resulted in the narrowing its band gap. Optical absorption bands at 520 and 654 nm correspond to the 4f electron transitions of Er<sup>3+</sup> further confirming visible light absorption. Infrared luminescence spectra showed a broad band centred at 1536 nm which is assigned to the <sup>4</sup> I<sub>13/2</sub> → <sup>4</sup> I<sub>15/2</sub> transition of Er<sup>3+</sup> . Visible upconverted emission spectra under 980 nm excitation exhibit a strong red luminescence with a main peak at 672 nm which is attributed to the <sup>4</sup> F<sub>9/2</sub> → <sup>4</sup> I<sub>15/2</sub> transition of Er<sup>3+</sup> . Power-dependent upconversion spectra confirmed that two photons participated in the upconversion mechanism. Enhancement in the intensities of both visible and infrared luminescence was observed when raising the concentration. The results pave the way for the potential applications of these nanocrystalline powders in energy harvesting applications such as infrared light upconverting layer in solar cells, light emitting diodes, infrared broadband sources and amplifiers, and biological labelling. Photon upconversion ; Nanocrystalline material ; Luminescence ; Materials science ; Infrared ; Analytical Chemistry (journal) ; Crystallite ; Phosphor ; Band gap ; Doping ; Visible spectrum ; Erbium ; Optoelectronics ; Chemistry ; Optics ; Nanotechnology Luminescence Properties of Advanced Materials ; Gas Sensing Nanomaterials and Sensors ; Perovskite Materials and Applications
Authors: Daniela Freyer | Melanie Pannach | Wolfgang Voigt
Source: Frontiers in Nuclear Engineering (article, 2023-09-27)
Field: Materials Science — Biomaterials

Solid–liquid equilibria of Sorel phases and Mg(OH)2 in the system Na-Mg-Cl-OH-H2O. Part II: Pitzer modeling For geochemical calculations of solubility equilibria between Sorel phases, Mg(OH) 2 , and oceanic salt solutions, the polythermal THEREDA dataset (based on the HMW model at 25°C) was extended. With both models, H + solution concentrations in equilibrium with Mg(OH) 2 (s) and the 3-1-8 Sorel phase at 25°C can be calculated in good agreement. In contrast, calculated OH − solution concentrations do not agree. Using the solubility constants (lg K s ) determined up to 60°C in Part I of this work, together with available solubility isotherms up to 120°C, temperature functions for the 3-1-8 phase (25°C–100°C), 2-1-4 phase (60°C–120°C), and 9-1-4 phase (100°C–120°C) were derived. In order to accurately model the OH − solution concentrations, it was necessary to implement the solution species Mg 3 (OH) 4 2+ (∆ R G m ° temperature function) in addition to the MgOH + already contained in the previous model. Finally, fitting Pitzer mixing coefficients for both species now allow the calculation of the solubility equilibria of Mg(OH) 2 (s) and the Sorel phases in agreement with the experimental data in the Mg-Cl-OH-H 2 O and Na-Mg-Cl-OH-H 2 O systems. Solubility ; Pitzer equations ; Chemistry ; Phase (matter) ; Thermodynamics ; Activity coefficient ; Phase equilibrium ; Solubility equilibrium ; Mixing (physics) ; Liquid phase ; Aqueous solution ; Analytical Chemistry (journal) ; Physical chemistry ; Chromatography ; Physics ; Organic chemistry Calcium Carbonate Crystallization and Inhibition ; Chemical and Physical Properties in Aqueous Solutions ; CO2 Sequestration and Geologic Interactions
Authors: Philipp Rüßmann | Masoud Bahari | Stefan Blügel | Björn Trauzettel
Source: arXiv (Cornell University) (preprint, 2023-07-26)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Inter-orbital Cooper pairing at finite energies in Rashba surface states Multi-band effects in hybrid structures provide a rich playground for unconventional superconductivity. We combine two complementary approaches based on density-functional theory (DFT) and effective low-energy model theory in order to investigate the proximity effect in a Rashba surface state in contact to an $s$-wave superconductor. We discuss these synergistic approaches and combine the effective model and DFT analysis at the example of a Au/Al heterostructure. This allows us to predict finite-energy superconducting pairing due to the interplay of the Rashba surface state of Au, and hybridization with the electronic structure of superconducting Al. We investigate the nature of the induced superconducting pairing and quantify its mixed singlet-triplet character. Our findings demonstrate general recipes to explore real material systems that exhibit inter-orbital pairing away from the Fermi energy. Pairing ; Superconductivity ; Density functional theory ; Condensed matter physics ; Physics ; Cooper pair ; Heterojunction ; Singlet state ; Fermi surface ; Electronic structure ; Quantum mechanics Iron-based superconductors research ; Surface and Thin Film Phenomena ; Superconductivity in MgB2 and Alloys
Authors: N. Kumar | R. M. Smertin | B.S. Prathibha | А. В. Нежданов | М. Н. Дроздов | В. Н. Полковников | Н. И. Чхало
Source: Journal of Physics D Applied Physics (article, 2023-05-17)
Field: Materials Science — Materials Chemistry

Raman scattering studies of Si/B<sub>4</sub>C periodic multilayer mirrors with an operating wavelength of 13.5 nm Abstract In order to obtain mirrors with a minimum value of residual stress, periodic multilayer mirrors composed of Si/B 4 C were deposited by magnetron sputtering with change in pressure of sputtering Ar gas. The microstructure and phase of Si and B 4 C was manipulated by the pressure of Ar gas which overall affected the stress in the mirrors. The minimum stress was obtained at higher pressure of sputter Ar gas, which showed the formation of amorphous boron, amorphous B 4 C, free carbon atoms and amorphous carbon structure in the B 4 C layers, investigated by Raman scattering spectroscopy. In Raman spectroscopy, a transverse optical (TO) mode of amorphous Si was shifted to lower frequency with increase in Ar gas pressure, which indicated relaxation of stress, also confirmed by the curvature measurement of mirrors. However, in the case of high residual stress, the amorphous B 4 C was a prominent phase in this layer and the frequency of the TO mode of amorphous Si was blue-shifted. Microstructure and stress affected the interfaces and modulation of the periodicity of the Si/B 4 C mirrors, investigated by secondary ion mass spectroscopy, which influenced the reflectivity of the mirrors. Raman spectroscopy ; Amorphous solid ; Materials science ; Sputter deposition ; Sputtering ; Microstructure ; Analytical Chemistry (journal) ; Raman scattering ; Residual stress ; Amorphous carbon ; Spectroscopy ; Optics ; Thin film ; Crystallography ; Chemistry ; Composite material ; Nanotechnology Diamond and Carbon-based Materials Research ; Advanced Surface Polishing Techniques ; Metal and Thin Film Mechanics
Authors: Zhengyi Chen | H. Dannerbauer | M. D. Lehnert | Bjorn Emonts | Qiusheng Gu | J. R. Allison | Jaclyn B. Champagne | N. A. Hatch | B. Indermuehle | R. P. Norris | José Manuel Pérez-Martínez | H. J. A. Röttgering | P. Serra | N. Seymour | Rhythm Shimakawa | A. P. Thomson | Caitlin M. Casey | C. De Breuck | G. Drouart | Tadayuki Kodama | Yusei Koyama | Claudia Lagos Urbina | Peter J. Macgregor | G. K. Miley | J. M. Rodríguez-Espinosa | Miguel Sánchez-Portal | B. Ziegler
Source: arXiv (Cornell University) (preprint, 2023-10-08)
Field: Chemistry — Spectroscopy

COALAS II. Extended molecular gas reservoirs are common in a distant, forming galaxy cluster This paper presents the results of 475 hours of interferometric observations with the Australia Telescope Compact Array towards the Spiderweb protocluster at \(z=2.16\). We search for large, extended molecular gas reservoirs among 46 previously detected CO(1-0) emitters, employing a customised method we developed. Based on the CO emission images and position-velocity diagrams, as well as the ranking of sources using a binary weighting of six different criteria, we have identified 14 robust and 7 tentative candidates that exhibit large extended molecular gas reservoirs. These extended reservoirs are defined as having sizes greater than 40 kpc or super-galactic scale. This result suggests a high frequency of extended gas reservoirs, comprising at least \(30 \%\) of our CO-selected sample. An environmental study of the candidates is carried out based on N-th nearest neighbour and we find that the large molecular gas reservoirs tend to exist in denser regions. The spatial distribution of our candidates is mainly centred on the core region of the Spiderweb protocluster. The performance and adaptability of our method are discussed. We found 13 (potentially) extended gas reservoirs located in nine galaxy (proto)clusters from the literature. We noticed that large extended molecular gas reservoirs surrounding (normal) star-forming galaxies in protoclusters are rare. This may be attributable to the lack of observations low-J CO transitions and the lack of quantitative analyses of molecular gas morphologies. The large gas reservoirs in the Spiderweb protocluster are a potential source of the intracluster medium seen in low redshift Virgo- or Coma-like galaxy clusters. Astrophysics ; Galaxy ; Physics ; Cluster (spacecraft) ; Redshift ; Weighting ; Computer science Spectroscopy and Laser Applications ; Astrophysics and Star Formation Studies ; Galaxies: Formation, Evolution, Phenomena
Authors: Wilson Phung | Corey E. Bakalarski | Trent Hinkle | Wendy Sandoval | Michael T. Marty
Source: ChemRxiv (preprint, 2023-07-02)
Field: Chemistry — Spectroscopy

The UniDec Processing Pipeline for Rapid Analysis of Biotherapeutic Mass Spectrometry Data Recent advances in native mass spectrometry (MS) and denatured intact protein MS have made these techniques essential for biotherapeutic characterization. As MS analysis has increased in throughput and scale, new data analysis workflows are needed to provide rapid quantitation from large datasets. Here, we describe the UniDec Processing Pipeline (UPP) for the analysis of batched biotherapeutic intact MS data. UPP is built into the UniDec software package, which provides fast processing, deconvolution, and peak detection. The user and programming interfaces for UPP read a spreadsheet that contains the data file names, deconvolution parameters, and quantitation settings. After iterating through the spreadsheet and analyzing each file, it returns a spreadsheet of results and HTML reports. We demonstrate the use of UPP to measure correct pairing percentage on a set of bispecific antibody data and to measure drug-to-antibody ratios from antibody-drug conjugates. Moreover, because the software is free and open-source, users can easily build on this platform to create customized workflows and calculations. Thus, UPP provides a flexible workflow that can be deployed in diverse settings and for a wide range of biotherapeutic applications. Workflow ; Pipeline (software) ; Computer science ; Deconvolution ; Software ; Measure (data warehouse) ; Throughput ; Set (abstract data type) ; Data mining ; Database ; Operating system ; Algorithm ; Programming language Advanced Proteomics Techniques and Applications ; Metabolomics and Mass Spectrometry Studies ; Mass Spectrometry Techniques and Applications