Group IIIB Elements Research Articles

The A-15-type superconducting hydride La4H23: a nanograined structure with low strain, strong electron-phonon interaction, and a moderate level of nonadiabaticity

Abstract For seven decades, when referring to A-15 superconductors, we meant metallic A3B alloys (where A is a transition metal, and B is group IIIB and IVB elements) discovered by Hardy and Hulm (1953 Phys. Rev. 89 884). Nb3Ge exhibited the highest superconducting transition temperature, Tc = 23K, among these alloys. One of these alloys, Nb3Sn, is the primary material in modern applied superconductivity. Recently, Guo et al (2024 Natl Sci. Rev. nwae149, https://doi.org/10.1093/nsr/nwae149) extended the family of superconductors where the metallic ions are arranged in the beta tungsten (A-15) sublattice by observation of Tc ,zero = 81K in the La4H23 phase compressed at P = 118 GPa. Despite the fact that La4H23 has much lower Tc in comparison with the near-room-temperature superconducting LaH10 phase (Tc ,zero = 250K at P ∼ 200 GPa) discovered by Drozdov et al (2019 Nature 569 531), La4H23 holds the record for the highest Tc within the A-15 family. Cross et al (2024 Phys. Rev. B 109 L020503) confirmed the high-temperature superconductivity in compressed La4H23. In this paper, we analyzed available experimental data measured in La4H23 and found that this superconductor exhibits a nanograined structure, 5.5 nm ⩽ D ⩽ 35 nm, low crystalline strain, | ε | ⩽ 0.003, strong electron–phonon interaction, 1.5 ⩽ λe-ph⩽ 2.55, and a moderate level of nonadiabaticity, 0.18 ⩽ Θ D /T F ⩽ 0.22 (where Θ D is the Debye temperature, and T F is the Fermi temperature). We found that the derived Θ D /T F and Tc /T F values for the La4H23 phase are similar to those in MgB2, cuprates, pnictides, and the near-room-temperature superconductors H3S and LaH10. To the memory of Martin J. Ryan, man and scientist who taught EFT the intricacies of X-ray diffraction.

Realizing ultralow thermal conductivity in Cu3SbSe4 via all-scale phonon scattering by co-constructing multiscale heterostructure and IIIB element doping

This article attempts to realize ultralow lattice thermal conductivity in Cu3SbSe4 by substitution Sb site by IIIB elements (Sc/Y), the facial microwave reaction were chosen to fabricate the above samples. The results show that group IIIB elements combined with multiscale heterostructure can effectively suppress the lattice thermal conductivity in Cu3SbSe4 system, resulting in a typical low value of 0.491 W/m/K and 0.481 W/m/K in Cu3Sb0.92Sc0.08Se4 and Cu3Sb0.92Y0.08Se4 at 623 K, respectively. Eventually, a peaking zT value of 0.47 and 0.46 can be obtained for each doping sample. This research highlights a novel strategy by co-constructing multiscale heterostructure and IIIB elements doping for realizing multiscale phonon scattering in Cu3SbSe4 materials.

Effects of doping IIIB elements (Al, Ga, In) on thermoelectric properties of nanostructured n-type filled skutterudite compounds

The optimization of the filler composition and nanostructuring is crucial for improving the thermoelectric properties of filled skutterudite compounds. Nevertheless, their simultaneous optimization is often difficult. In this study, group IIIB elements, which were not systematically investigated before as filler elements, were emphasized. Results revealed that group IIIB elements, particularly Al, effectively enhanced the electrical conductivity and decreased the lattice thermal conductivity. Nanostructured samples exhibited an ∼20% enhancement of the thermoelectric figure-of-merit ZT, whereas the effects of the Al filler were not tangible in ZT because of the low solubility limit of Al and the high thermal conductivity of electron carriers.

Yttrium-Doped Zinc Oxide as a Terawatt-Scale Transparent Conducting Oxide

The desirable features of an ideal transparent conducting oxide for terawatt-scale solar cells include abundant raw materials, low cost, high performance, and low process temperature. In this paper we examine all the Group IIIA and IIIB elements as potential n-type dopants for ZnO and suggest yttrium as an ideal dopant for this purpose. Experimental results on electrodeposited yttrium-doped ZnO are presented. The lowest resistivity in yttrium-doped ZnO is 6.3E-5 Ohm-cm, while the average resistivity is ~2E-4 Ohm-cm. The maximum process temperature is 300°. The transmittance of yttrium-doped ZnO is ~80%. Thermal stability of yttrium-doped ZnO is also investigated. It has a real chance to become an industry standard transparent conducting oxide for terawatt-scale solar cells, as its performance is comparable to indium tin oxide, its deposition is solution-based, and yttrium is abundant.

Optimizing Band-Edge High-κ/Metal Gate n-MOSFETs with ALD Lanthanum Oxide Cap Layers: Oxidant and Positioning Effects

We have previously shown that by varying the position of threshold voltage adjustment cap layers within the gate stack, as well as the oxidant used during processing, it is possible to tune the threshold voltage of n-FET devices, and to concurrently realize a scaling benefit by incorporating group IIA and group IIIB elements into gate dielectrics deposited by metalorganic atomic layer deposition. In this report we have focused on lanthanum oxide cap layers that provide band edge nFET work functions. We compare our previously reported results with ozone oxidation with newly developed processes using oxygen and water as oxidants that result in highly scaled devices with band edge work functions and acceptable leakage characteristics.

Magnetism induced by nonmagnetic dopants in zinc-blende SiC: First-principle calculations

Magnetism induced by the nonmagnetic dopants in the zinc-blende SiC (3C-SiC) is investigated by first-principle calculations. The atoms of the first 20 elements in the periodic table except inert gas are used to replace either Si or C atoms as dopants. We find that some nonmagnetic substitutional dopants (mainly the Group IA, Group IIA, Group IIIB, and Group VIIB elements) prefer the spin-polarized ground states with local magnetic moments. In general, the condition for obtaining the local magnetic moments and the magnetic ground state requires that the dopants are p-type and have large electronegativity difference from the neighboring host atoms. The magnetic moments can be tuned over a range between 1 µB and 3 µB by doping with the nonmagnetic elements. The nearest-neighbor exchange couplings J0 between the local magnetic moments are quite large and the codoping method is proposed to increase the dopant concentration. These imply that the nonmagnetic doping in SiC may exhibit collective magnetism. Moreover, the Group IIA Mg and Ca atoms substituting the preferred Si atoms favor the ferromagnetic ground states with the half-metallic electronic properties, which suggests that Mg or Ca substitutional doping on the Si sites in SiC could be a potential route to fabricating the diluted magnetic semiconductors.

Engineering Band-Edge High-κ/Metal Gate n-MOSFETs with Cap Layers Containing Group IIA and IIIB Elements by Atomic Layer Deposition

This paper presents studies performed in engineering high-k metal gate stacks by using capping layers containing Group IIA and IIIB elements. Both high-k gate dielectric (HfO2) and capping materials, namely, the oxides of barium, lanthanum and yttrium are deposited by atomic layer deposition (ALD) to offer superior process control and flexibility. Position specific insertion of cap layers into the gate stack is studied and the device tradeoffs are highlighted. The magnitude of Vt shift is correlated to the electronegativity of the cap layer species and its relative position in the gate stack. For a given cap position, BaO provides the maximum Vt shift, followed by La2O3 and Y2O3 caps. Ozone based ALD processes are shown to adversely impact Tinv scaling due to the re-growth of the interface layer between the high-k and the silicon substrate. Significant improvements in Tinv scaling are obtained by migrating to a water based ALD process.

Light emission due to the quantum confinement of carriers in silicon‐based nanostructures

AbstractIn the field of Si nanoscale ultralarge‐scale integration, the quantum confinement effect is undesirable with respect to the device characteristics and performance because the carriers are entirely confined in nanoscale or low‐dimensional structures. Significant efforts are being made with regard to the positive use of the quantum confinement effect in Si nanoscale structures. One such attempt is related to the use of Si optoelectronics and photonics for optical interconnections within a Si chip. In this study, the intrinsic electronic structures in the Si‐based nanostructures with different dimensions and sizes as candidates for Si optoelectronics were investigated by the DV‐Xα molecular orbital calculation, which is advantageous to simulate the valence band structures for nanomaterials. We discuss the shift of a light emission peak to a higher energy due to the quantum confinement of carriers in the Si‐based nanostructures, which depends on the sizes and numbers of structural dimensions, on the basis of the calculated results. Also, effect of doping of group IIIB and VB elements in the periodic table on the extrinsic electronic structures of the Si‐based nanostructures were clarified by combining the Vienna ab‐initio code for determining the relaxation structures around the dopants with the DV‐Xα method for simulating the valence band structures. The results obtained are useful as a measure of possibility of the Si‐based nano‐structured materials for optoelectronics. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009

Engineering Band-Edge High-κ/Metal Gate n MOSFETs with Cap Layers Containing Group IIA and IIIB Elements by Atomic Layer Deposition

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Defect and electronic structures of acceptor substituted lead titanate

The defects and electronic structures of the group IIIB (Al, Ga, In, and Tl) and group VB (Sb and Bi) element substituted lead titanates were studied using density functional theory calculations. All substitutes are found to favor immobile acceptor-oxygen-vacancy-acceptor defect clusters, which weaken the space charge effects by limiting the motions of oxygen vacancies. Furthermore, we found that the group IIIB and group VB substitutes take two distinct defect-cluster structures, respectively, along the z direction and in the xy plane, mainly due to the difference in the ionic size and the electronegativity. While the domain pinning enforced by the tail-to-tail polarization patterns along the z direction are relieved by the group IIIB substitutes, the group VB substitutes induce head-to-head polarization patterns in the xy plane, which make the domain pinning effects even weaker.

Prediction of Defects in PZT Thin Film Using Ab-Initio Method

This paper reviews our systematic and exhaustive studies on the lead zirconate titanate doped with dopants using ab initio density functional theory calculations in order to understand the mechanisms behind the dopings. Different candidates of dopants were selected by screening the periodical table of elements. In our studies, group VA, VIA elements (B-site donors), group IIA elements (A-site donors), group IIIB elements (B-site acceptors), and group VB elements (A-site donor, B-site acceptor/donors) are investigated as dopants in PZT. We found that there exist different mechanisms behind the improved ferroelectric properties, especially the fatigue behaviors. For donors doping, diluted oxygen vacancy concentration and reduced electronic suppression of polarization contribute to the fatigue-free behaviors of donor doped PZT. On the other hand, for acceptor doping, acceptor-oxygen-vacancy-acceptor clusters are energetically preferred, which greatly reduce the oxygen vacancy mobility and the domain pinning effects. We expect that this study could provide important information for the experiments on PZT-based materials.

Ab initio and DFT studies on vibrational spectra of some halides of group IIIB elements

The vibrational spectra of some group IIIB elements halides MX 3 and their dimmers, M 2X 6 (M = Sc(III), Y(III), La(III); X = F, Cl, Br, I), have been systematically investigated by ab initio restricted Hartree–Fock (RHF) and density functional B3LYP methods with LanL2DZ and SDD basis sets. The optimized geometries and calculated vibrational frequencies are evaluated via comparison with experimental values. The vibrational frequencies, calculated by two methods with different basis sets, are compared to each other. The effect of the methods and the basis sets used on the calculated vibrational frequencies are discussed. Some vibrational frequencies of these complexes are also predicted.

Eutectoid equilibria relationships in binary plutonium phase diagrams

The applicability of a universal relationship of invariant transformations for analyzing eutectoid transformations in binary plutonium systems is demonstrated in this article. This relationship requires a favorable temperature factor for the formation of eutectoid reactions. This work confirms the validity of previously established values for decomposition of δ-phase solid solution and compounds of plutonium with group III-B elements at atmospheric and elevated pressures. It is demonstrated that in alloys of plutonium with elements of group III-B, the parameters of eutectoid transformations of the δ-phase change monotonically with increasing atomic number of the element.

Hydrogen–oxygen fuel cells

A hydrogen/oxygen fuel cell includes an electrolyte which is solid at room temperature, has opposing faces, conducts protons, and is comprised of at least one of (a) at least one oxide of at least one element selected from the group consisting of Group IVB, VB, VIB, and VIII elements of the Periodic Table, (b) silicon dioxide, and (c) at least one fluoride of at least one element selected from the group consisting of Group IIA and IIIB elements of the Periodic Table. Also included are a hydrogen electrode which is applied to one face of the opposing faces of the electrolyte, is hydrogen permeable, and is negatively charged in use; and an oxygen electrode which is applied to another face of the opposing faces of the electrolyte, is hydrogen permeable, and is positively charged in use. A hydrogen-containing gas chamber is provided so as to be in communication with the hydrogen electrode; and an oxygen-containing gas chamber is provided so as to be in communication with the oxygen electrode.

Some Regularities in Eutectoid Transformations in Binary Systems of Plutonium

It is shown that a universal relation for nonvariant transformations can be used to analyze eutectoid transformations in binary systems of plutonium. It is determined that a favorable temperature factor is necessary for eutectoids to form. A check taking account of the dependence of the parameters of eutectoid equilibria in phase diagrams for plutonium with group III-B elements confirmed that the previously determined values for the decomposition of δ-solid solution and compounds at atmospheric and higher pressures are correct. The temperature of the eutectoid transformation of the δ phase increases with the atomic number of the element in the series of group III-B elements: Al, Ga, In, and Tl.

An estimation of the ionization potentials of actinides from a simple dependence of the aqueous standard potentials on the ionization potentials of elements including lanthanides

It was found recently that the ionization potentials and electron affinities of elements in the gaseous state are linked to the standard potentials of their principal oxidation states in aqueous solutions by simple linear relations. These relations are characteristic for each group of elements of the periodic table. In the case of the actinides, in the absence of adequate data on their ionization potentials, the linear relation obtained for the group IIIB elements (including lanthanides) has been found useful for estimating them using the available data on their standard oxidation potentials (obtained in most cases by radio-polarography).

Comparison of carrier elements for coprecipitation and graphite-furnace atomic absorption spectrometry

The group IIIB elements (aluminum, gallium and indium) and iron(III) were studied from the standpoint of the advantageous combination of coprecipitation and graphite-furnace atomic absorption Spectrometry (GFAAS). Milligram quantities of four hydroxides were precipitated at different pH's from solutions containing traces of copper(II) and cadmium(II) ions, in order to examine the effect of pH on the coprecipitation. Almost similar results were obtained for gallium, indium and iron hydroxides, with which the copper and cadmium were coprecipitated nearly completely at pH>7. In case of aluminum hydroxide, the optimal pH range was narrow because of the redissolution of the precipitate in alkaline solutions. The removal of indium carrier was successfully achieved by volatilization as bromide at the pyrolysis stage in GFAAS, otherwise serious background absorption interfered with the trace determination. Volatilization loss of cadmium was eliminated by adding a small amount of miourea. Gallium carrier was mostly removed as chloride, but large background absorption still occurred in the determination of cadmium.

Thermal conductivity in A3B intermetallic compounds based on iron and nickel

Thermal conductivity of A 3 B intermetallic compounds, where A denotes iron or nickel and B denotes group IIIb or IVb elements, is investigated by a laser-flash method. Among six kinds of L1 2 compounds, the largest thermal conductivity observed is 32 8 Wm −1 K −1 of Ni 3 Ga. In Fe 3 Ga and Fe 3 Ge, three polymorphs, i.e. L1 2 , D0 19 and D0 3 , can be achieved by performing a suitable heat treatment. Thermal conductivity of the D0 19 phase is quite close to that of the L1 2 phase, while the DO, phase shows smaller values. In most A 3 B compounds, the measured thermal conductivities tend to decrease as the position of constituent B becomes horizontally more distant from that of constituent A in the periodic table.

Classification of emission lines of the Group IIIB elements, aluminium, gallium and indium, excited by Grimm glow discharge plasmas using several different plasma gases

In order to clarify the spectroscopic characteristics of the Group IIIB elements in Grimm glow discharge plasmas, the relative intensities of their emission lines in the wavelength range 160–800 nm were investigated and tabulated when using different plasma gases, viz., argon, neon, argon–helium and neon–helium. It was characteristic of the glow discharge light source that the emission spectra observed were strongly dependent on the type of plasma gas employed. Extremely intense ionic lines were observed when neon rather than argon was employed as the plasma gas. Furthermore, different groups of ionic lines could be observed only in the helium-containing plasmas. The excitation of these ionic lines can be principally attributed to charge-transfer collisions between the analyte atoms and the plasma gas ions.

Prediction of a further irregularity in the electron filling of subshell: Lu-(Xe)4f145d16s26p1 and its relation to the group IIIB anions

Dirac-Hartree-Fock theory (DHF), and density functional theory Hartree-Fock system (DFT-HF) calculations predict that Lu- (Z=71) is stable in the (Xe)4f145d16s26p1 odd-parity electron configuration and is not bound in the commonly assumed (Xe)4f145d26s2 even-parity configuration of Hf0 (Z=72). Combining the results of these methods gives an electron affinity approximately=7+or-4 Hartree. The Hartree-Fock energy dominates the crossover from even to odd parity ground state as Z is lowered from 72 to 71 in this 72 electron system. The relativistic effects, which are inherent to the DHF method, are important in unbinding the even-parity state and have been included perturbatively in the DFT-HF calculations. The very large experimental sd interconfiguration energy of Lu0 is used to support the conclusion that the even-parity configuration is unstable. A comparison of the electron configuration of singly charged (+or-) and neutral Lu with those of the group IIIB elements indicates that Lu is most similar to Y.