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At least 181 records · Page 10

Moderate-temperature solution-processed synthesis of incommensurate Sr 8/7 TiS 3 thin films and rod-shaped nanocrystals

The chalcogenide perovskite family has been steadily gaining increasing attention from the research community due to its optoelectronic properties and potential for diverse applications. While BaZrS 3 and BaTiS 3 have been the most extensively studied, other promising compounds in this family, such as Sr x TiS 3 (1.05 < x < 1.22), are now being explored for various optical, optoelectronic, and energy storage applications. However, challenges remain in achieving the low-temperature synthesis of Sr x TiS 3 . In this study, we report, for the first time, the synthesis of Sr x TiS 3 nanocrystals at temperatures below 400 °C. The synthesized nanocrystals exhibit a rod-like morphology. Additionally, we have developed solution-processing routes to synthesize phase-pure Sr x TiS 3 thin films, marking the first reported instance of such films, at temperatures below 600 °C. We also demonstrate the solid-state synthesis of Sr x TiS 3 powder below 600 °C. Our work paves the way for new and exciting application avenues for Sr x TiS 3 .

36 MATERIALS SCIENCE↗

Revealing the intrinsic transport properties of antiperovskite Sr 3 SnO thin films

A topologically non-trivial band structure and reports of superconductivity have motivated significant investigation into the transport properties of the antiperovskite oxide Sr 3 SnO. Phase-pure films of Sr 3 SnO can be grown by molecular beam epitaxy, but they do not have the required extremely high hole-doping densities (>1 × 10 21 cm –3 ) for which superconductivity has been observed in bulk materials. To date, high hole-doping densities have been achieved via inducing strontium deficiency, which inevitably results in impurity phases. Here, we show that indium acts as an effective hole dopant in Sr 3 SnO and can be used to achieve high hole doping densities in stoichiometric films. Films with carrier densities as high as 1.5 × 10 21 cm –3 remain non-superconducting. We, therefore, suggest that Sr 3 SnO is probably not an intrinsic superconductor. A second question addressed in this work is the measurement of the intrinsic electrical transport properties of Sr 3 SnO, given its rapid degradation in air. We show that even in inert atmospheres, reducing the time needed for establishing electrical contacts and protecting the Sr 3 SnO film result in improved electrical properties. Here, we demonstrate low carrier density films (4 × 10 18 cm –3 ) with carrier mobilities of 400 cm 2 V –1 s –1 at 10 K.

36 MATERIALS SCIENCE↗

Single crystal growth and electronic structure of Rh-doped Sr 3 Ir 2 O 7

Ruddlesden-Popper iridate Sr 3 Ir 2 O 7 is a spin–orbit coupled Mott insulator. Hole doped Sr 3 Ir 2 O 7 provides an ideal platform to study the exotic quantum phenomena that occur near the metal–insulator transition (MIT) region. Rh substitution of Ir is an effective method to induce hole doping into Sr 3 Ir 2 O 7 . However, the highest doping level reported in Sr 3 (Ir 1− x Rh x ) 2 O 7 single crystals was only around 3%, which is far from the MIT region. In this paper, we report the successful growth of single crystals of Sr 3 (Ir 1− x Rh x ) 2 O 7 with a doping level of ~ 9%. The samples have been fully characterized, demonstrating the high quality of the single crystals. Transport measurements have been carried out, confirming the tendency of MIT in these samples. The electronic structure has also been examined by angle-resolved photoemission spectroscopy (ARPES) measurements. Our results establish a platform to investigate the heavily hole doped Sr 3 Ir 2 O 7 compound, which also provide new insights into the MIT with hole doping in this material system.

Physics↗

Electronic properties of epitaxial La 1- x Sr x RhO 3 thin films

Here, we report on the synthesis and electronic properties of epitaxial perovskite La 1- x Sr x RhO 3 thin films. Thin films with a Sr content ranging from $\textit{x}$ = 0 to 0.5 have been grown using molecular beam epitaxy. Transport and x-ray photoemission spectroscopy data reveal an insulator-metal-insulator transition, accompanied by a $\textit{p-}$ to $\textit{n}-$ type carrier change observed in Hall measurements. Combined with theoretical calculations, we find that the addition of Sr does not directly dope carriers into the conduction band, but rather induces localized Rh 4$\textit{d}$ states within the LaRhO 3 band gap. The bandwidth of the impurity band increases with Sr content, eventually causing the valence band (VB) and the localized Rh 4$\textit{d}$ band to overlap, which explains the first insulator-to-metal transition occurring at $\textit{x}$ = 0.35. For Sr content $\textit{x}$ > 0.4, possible cation ordering results in an increase of the gap between the VB and the Rh 4$\textit{d}$ band, leading to the second metal-to-insulator transition. We map out the electronic phase diagram of the Sr-doped LaRhO 3 system and suggest strategies to engineer the electronic states in rhodate systems via delocalizing the Rh 3+ states.

36 MATERIALS SCIENCE↗

Cross sections and calculated yields of some radionuclides of yttrium, strontium and rubidium formed in proton-induced reactions on enriched strontium-86: possibility of production of 85g Sr, 83 Rb and 82m Rb in no-carrier-added form

Here, cross sections of the 86 Sr(p,3n) 84m Y, 86 Sr(p,αn) 82m Rb, and 86 Sr(p,x) 85g Sr reactions were measured from their respective thresholds up to 16.2 MeV and from 23.0 to 44.1 MeV at FZJ, and from 14.3 to 24.5 MeV at LBNL, using 96.4% enriched 86 SrCO 3 as target material. Thin targets prepared by sedimentation were irradiated with protons in a stacked-form, and the induced radioactivity was measured by high-resolution γ-ray spectrometry. Nuclear model calculations based on the code TALYS reproduced our experimental cross section data well. From the excitation functions, the integral yields of the above three radionuclides were calculated. The yield of 85g Sr via the natSr(n,γ) process was also measured using the TRIGA Mark-II reactor at AERE, Savar. A comparison of the reactor and cyclotron production of carrier-added 85g Sr is given. The production possibilities of the three investigated radionuclides in no-carrier-added forms at a 30 MeV cyclotron via new routes are discussed.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

Rb-Sr studies of CI and CM chondrites

Rb-Sr whole rock analyses have been performed on 2 CI and 3 CM chondrites. Four of these stones (Ivuna, Orgueil, Cold Bokkeveld and Erakot) were previously studied in this laboratory and were shown to be discordant from a 4.6 Gyr isochron. The fifth, Murchison, was not previously studied. The new data support the discordance of the first four stones, and indicate that Murchison is also discordant. Studies of Sr isotope ratios in unspiked Orgueil show that the discordance is not due to inhomogeneities in the Sr-84/Sr-86 ratio caused by incomplete mixing of nucleosynthesis products. In order to gauge the effects of weathering, two leaching experiments were performed on fresh, interior samples of Murchison; one for a period of 1.5 hr and the other for 117 hr. The results indicate that the relative solubility of nonradiogenic Sr is approximately twice that of Rb and radiogenic Sr is more soluble than the nonradiogenic Sr.

Mittlefehldt, D. W.↗

Oxidation of the Si(100) surface promoted by Sr overlayer - An X-ray photoemission study

The interaction of strontium films with the underlaying Si (100) surface and the Sr-promoted low-temperature oxidation of Si were investigated, using XPS, at three different Sr coverages (theta): theta = 0.55 monolayer (ML), theta = 1 ML, and theta = 1.85 ML. Oxygen adsorption was studied both at room temperature and at 500 C, and at oxygen exposures up to 2 x 10 to the 6th L (1 L = 10 to the -6th torr) and 2 x 10 to the 5th L, respectively. The XPS spectra of the Si2p, O1s, and Sr3d core levels were measured for the atomically clean Si, the Sr-covered Si, and for the Sr-covered Si after each oxygen exposure. Results indicate that Sr interacts with the Si(100) surface forming a strong ionic bond, and that Sr promotes the oxidation of the Si (100) surface.

Mesarwi, A.↗

Derivation of Apollo 14 High-Al Basalts at Discrete Times: Rb-Sr Isotopic Constraints

Pristine Apollo 14 (A-14) high-Al basalts represent the oldest volcanic deposits returned from the Moon [1,2] and are relatively enriched in Al2O3 (>11 wt%) compared to other mare basalts (7-11 wt%). Literature Rb-Sr isotopic data suggest there are at least three different eruption episodes for the A-14 high-Al basalts spanning the age range approx.4.3 Ga to approx.3.95 Ga [1,3]. Therefore, the high-Al basalts may record lunar mantle evolution between the formation of lunar crust (approx.4.4 Ga) and the main basin-filling mare volcanism (<3.85 Ga) [4]. The high-Al basalts were originally classified into five compositional groups [5,6], and then regrouped into three with a possible fourth comprising 14072 based on the whole-rock incompatible trace element (ITE) ratios and Rb-Sr radiometric ages [7]. However, Rb-Sr ages of these basalts from different laboratories may not be consistent with each other because of the use of different 87Rb decay constants [8] and different isochron derivation methods over the last four decades. This study involved a literature search for Rb-Sr isotopic data previously reported for the high-Al basalts. With the re-calculated Rb-Sr radiometric ages, eruption episodes of A-14 high-Al basalts were determined, and their petrogenesis was investigated in light of the "new" Rb-Sr isotopic data and published trace element abundances of these basalts.

Hui. Hejiu↗

Materials Data on Sr(NiGe)2 by Materials Project

SrNi2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr is bonded in a 8-coordinate geometry to eight equivalent Ni and eight equivalent Ge atoms. All Sr–Ni bond lengths are 3.32 Å. All Sr–Ge bond lengths are 3.30 Å. Ni is bonded in a 4-coordinate geometry to four equivalent Sr and four equivalent Ge atoms. All Ni–Ge bond lengths are 2.38 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Sr, four equivalent Ni, and one Ge atom. The Ge–Ge bond length is 2.89 Å.

36 MATERIALS SCIENCE↗

Materials Data on Sr(PO3)2 by Materials Project

Sr(PO3)2 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.03 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.05 Å. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–3.04 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–2.96 Å. There are eight inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There is two shorter (1.50 Å) and two longer (1.61 Å) P–O bond length. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There is two shorter (1.50 Å) and two longer (1.61 Å) P–O bond length. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There is two shorter (1.50 Å) and two longer (1.61 Å) P–O bond length. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There is two shorter (1.50 Å) and two longer (1.61 Å) P–O bond length. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the twentieth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the twenty-second O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom.

36 MATERIALS SCIENCE↗

Materials Data on Sr(ClO2)2 by Materials Project

Sr(O2Cl)2 crystallizes in the orthorhombic Ccce space group. The structure is two-dimensional and consists of two Sr(O2Cl)2 sheets oriented in the (0, 1, 0) direction. Sr is bonded in a 8-coordinate geometry to eight equivalent O atoms. All Sr–O bond lengths are 2.65 Å. O is bonded in a trigonal planar geometry to two equivalent Sr and one Cl atom. The O–Cl bond length is 1.59 Å. Cl is bonded in a water-like geometry to two equivalent O atoms.

36 MATERIALS SCIENCE↗

Materials Data on Sr(HO)2 by Materials Project

Sr(OH)2 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to one H1+ and six O2- atoms. The Sr–H bond length is 2.57 Å. There are a spread of Sr–O bond distances ranging from 2.54–2.68 Å. In the second Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to one H1+ and six O2- atoms. The Sr–H bond length is 2.56 Å. There are a spread of Sr–O bond distances ranging from 2.50–2.64 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one Sr2+ and one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Sr2+ and one O2- atom. The H–O bond length is 0.98 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to three Sr2+ and one H1+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to three Sr2+ and one H1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to three Sr2+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to three Sr2+ and one H1+ atom.

36 MATERIALS SCIENCE↗

Materials Data on Sr(GeIr)2 by Materials Project

SrIr2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr is bonded in a 8-coordinate geometry to eight equivalent Ir and eight equivalent Ge atoms. All Sr–Ir bond lengths are 3.44 Å. All Sr–Ge bond lengths are 3.31 Å. Ir is bonded to four equivalent Sr and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing IrSr4Ge4 tetrahedra. All Ir–Ge bond lengths are 2.49 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Sr, four equivalent Ir, and one Ge atom. The Ge–Ge bond length is 2.81 Å.

36 MATERIALS SCIENCE↗

Materials Data on Sr(GaH)2 by Materials Project

Sr(GaH)2 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Sr(GaH)2 sheet oriented in the (0, 0, 1) direction. Sr is bonded in a hexagonal planar geometry to six equivalent H atoms. All Sr–H bond lengths are 2.59 Å. Ga is bonded in a single-bond geometry to one H atom. The Ga–H bond length is 1.70 Å. H is bonded to three equivalent Sr and one Ga atom to form a mixture of distorted corner and edge-sharing HSr3Ga trigonal pyramids.

36 MATERIALS SCIENCE↗

Materials Data on Sr(GePd)2 by Materials Project

SrPd2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr is bonded in a 8-coordinate geometry to eight equivalent Pd and eight equivalent Ge atoms. All Sr–Pd bond lengths are 3.40 Å. All Sr–Ge bond lengths are 3.41 Å. Pd is bonded in a 4-coordinate geometry to four equivalent Sr and four equivalent Ge atoms. All Pd–Ge bond lengths are 2.54 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Sr, four equivalent Pd, and one Ge atom. The Ge–Ge bond length is 2.67 Å.

36 MATERIALS SCIENCE↗

Materials Data on Sr(ClO)2 by Materials Project

Sr(OCl)2 crystallizes in the monoclinic C2/c space group. The structure is one-dimensional and consists of two Sr(OCl)2 ribbons oriented in the (0, 0, 1) direction. Sr is bonded in a 8-coordinate geometry to four equivalent O atoms. There are two shorter (2.49 Å) and two longer (2.50 Å) Sr–O bond lengths. O is bonded in a trigonal planar geometry to two equivalent Sr and one Cl atom. The O–Cl bond length is 1.67 Å. Cl is bonded in a distorted single-bond geometry to one O atom.

36 MATERIALS SCIENCE↗

Materials Data on Sr(Cu2Sn)2 by Materials Project

SrCu4Sn2 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Sr is bonded in a 8-coordinate geometry to eight equivalent Cu and eight equivalent Sn atoms. All Sr–Cu bond lengths are 3.27 Å. All Sr–Sn bond lengths are 3.65 Å. Cu is bonded in a 9-coordinate geometry to two equivalent Sr, three equivalent Cu, and four equivalent Sn atoms. There are one shorter (2.52 Å) and two longer (2.63 Å) Cu–Cu bond lengths. There are a spread of Cu–Sn bond distances ranging from 2.67–2.75 Å. Sn is bonded in a 12-coordinate geometry to four equivalent Sr and eight equivalent Cu atoms.

36 MATERIALS SCIENCE↗

Materials Data on Sr(ClO)2 by Materials Project

Sr(OCl)2 crystallizes in the orthorhombic Ccce space group. The structure is two-dimensional and consists of two Sr(OCl)2 sheets oriented in the (0, 1, 0) direction. Sr is bonded in a distorted body-centered cubic geometry to eight equivalent O atoms. There are a spread of Sr–O bond distances ranging from 2.62–2.80 Å. O is bonded in a 5-coordinate geometry to four equivalent Sr and one Cl atom. The O–Cl bond length is 1.71 Å. Cl is bonded in a single-bond geometry to one O atom.

36 MATERIALS SCIENCE↗