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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Er(MnGe)6 by Materials Project

ErMn6Ge6 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Er is bonded to eight Ge atoms to form distorted edge-sharing ErGe8 hexagonal bipyramids. There are two shorter (2.80 Å) and six longer (2.99 Å) Er–Ge bond lengths. Mn is bonded in a 12-coordinate geometry to six Ge atoms. There are a spread of Mn–Ge bond distances ranging from 2.52–2.69 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 8-coordinate geometry to one Er, six equivalent Mn, and one Ge atom. The Ge–Ge bond length is 2.54 Å. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Er and six equivalent Mn atoms. In the third Ge site, Ge is bonded in a 6-coordinate geometry to six equivalent Mn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(Ni2As)2 by Materials Project

Er(Ni2As)2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Er is bonded to six equivalent As atoms to form a mixture of distorted corner and edge-sharing ErAs6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are two shorter (2.89 Å) and four longer (2.91 Å) Er–As bond lengths. Ni is bonded in a 3-coordinate geometry to three equivalent As atoms. There are two shorter (2.39 Å) and one longer (2.41 Å) Ni–As bond lengths. As is bonded in a 9-coordinate geometry to three equivalent Er and six equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(MnSn)6 by Materials Project

ErMn6Sn6 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Er is bonded to eight Sn atoms to form distorted edge-sharing ErSn8 hexagonal bipyramids. There are two shorter (3.00 Å) and six longer (3.15 Å) Er–Sn bond lengths. Mn is bonded in a 12-coordinate geometry to six Sn atoms. There are a spread of Mn–Sn bond distances ranging from 2.74–2.83 Å. There are three inequivalent Sn sites. In the first Sn site, Sn is bonded in a 12-coordinate geometry to three equivalent Er and six equivalent Mn atoms. In the second Sn site, Sn is bonded in a 6-coordinate geometry to six equivalent Mn atoms. In the third Sn site, Sn is bonded in a 8-coordinate geometry to one Er, six equivalent Mn, and one Sn atom. The Sn–Sn bond length is 3.00 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(Co2Ge)2 by Materials Project

Er(Co2Ge)2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Er is bonded to six equivalent Ge atoms to form a mixture of distorted edge and corner-sharing ErGe6 octahedra. The corner-sharing octahedral tilt angles are 39°. There are two shorter (2.84 Å) and four longer (2.92 Å) Er–Ge bond lengths. Co is bonded in a 3-coordinate geometry to three equivalent Ge atoms. All Co–Ge bond lengths are 2.39 Å. Ge is bonded in a 9-coordinate geometry to three equivalent Er and six equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(PO2)3 by Materials Project

Er(PO2)3 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of two Er(PO2)3 sheets oriented in the (1, 0, 0) direction. there are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded in an octahedral geometry to six O2- atoms. There are four shorter (2.23 Å) and two longer (2.27 Å) Er–O bond lengths. In the second Er3+ site, Er3+ is bonded in an octahedral geometry to six O2- atoms. There are four shorter (2.24 Å) and two longer (2.25 Å) Er–O bond lengths. There are three inequivalent P3+ sites. In the first P3+ site, P3+ is bonded in a bent 120 degrees geometry to two equivalent O2- atoms. Both P–O bond lengths are 1.52 Å. In the second P3+ site, P3+ is bonded in a bent 120 degrees geometry to two equivalent O2- atoms. Both P–O bond lengths are 1.53 Å. In the third P3+ site, P3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.52 Å) and one longer (1.53 Å) P–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Er3+ and one P3+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Er3+ and one P3+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Er3+ and one P3+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Er3+ and one P3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2026

2D in-Plane Ordered MXene Nanosheets Derived from (Mo 2/3 Er 1/3 ) 2 AlC Rare-Earth i-MAX for Energy Storage Applications

MXenes have become one of the most versatile families of two-dimensional (2D) materials due to their high conductivity, hydrophilicity, and remarkable electrochemical performance. This has stimulated intense efforts to design and synthesize MXenes, including structurally unique in-plane ordered 2D MXenes called i-MXenes. Here, we have synthesized the quaternary rare earth (RE)-based i-MAX phase (Mo 2/3 Er 1/3 ) 2 AlC using an arc melting method, and the corresponding 2D i-MXene was then obtained through a LiF/HCl soft etching process. Literature studies have shown that Al and the RE element are etched out during the etching process, leading to the formation of pure vacancy-ordered Mo1.33C 2D i-MXene. However, our investigation reveals that upon exposure to a fluorine solution, the i-MAX phase forms RE fluoride impurities, which are challenging to remove through HCl−DI water washing and persist in the final product, resulting in impure Mo 1.33 C@Er i-MXene. These results were confirmed by various characterizations such as X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning transmission electron microscopy. Although the Mo 1.33 C@Er electrode showed a 24-fold increase in specific capacitance compared to its parent i-MAX phase, it still exhibited a high charge-transfer resistance arising from the insulating nature of RE fluoride byproducts, which adversely influence the overall capacitance behavior of the synthesized 2D Mo 1.33 C@Er i-MXenes. This study contributes to identifying pathways for the preparation of pure 2D i-MXenes from RE-based i-MAX phases and developing improved synthesis methods. With additional process optimization, the 2D i-MXene holds a strong potential for electrochemical energy storage applications. Additionally, the electronic structures of Mo 1.33 C were theoretically studied using first-principles density functional theory calculations, which revealed that pristine Mo 1.33 C is metallic, and this metallic nature is preserved even with −O, −F, and mixed functionalization.

chemical structure↗
DOE OSTI2024

Optical and spin coherence of Er spin qubits in epitaxial cerium dioxide on silicon

Robust spin-photon interfaces with optical transitions in the telecommunication band are essential for quantum networking technologies. Erbium (Er) ions are the ideal candidate with environmentally protected transitions in telecom-C band. Finding the right technologically compatible host material to enable long-lived spins remains a major hurdle. We introduce a new platform based on Er ions in cerium dioxide (CeO 2 ) as a nearly-zero nuclear spin environment (0.04%) epitaxially grown on silicon, offering silicon compatibility for opto-electrical devices. Our studies focus on Er 3+ ions and show a narrow homogeneous linewidth of 440 kHz with an optical coherence time of 0.72 μs at 3.6 K. The reduced nuclear spin noise enables a slow spin-lattice relaxation with a spin relaxation time up to 2.5 ms and an electron spin coherence time of 0.66 μs (in the isolated ion limit) at 3.6 K. These findings highlight the potential of Er 3+ :CeO 2 platform for quantum networks applications.

Zhang, Jiefei↗
DOE OSTI2020

Epitaxial Er-doped Y 2 O 3 on silicon for quantum coherent devices

Rare-earth ions have incomplete 4f shells and possess narrow optical intra-4f transitions due to shielding from electrons in the 5s and 5p orbitals, making them good candidates for solid-state optical quantum memory. The emission of Er 3+ in the telecom C-band (1530 nm – 1565 nm) makes it especially attractive for this application. In order to build practical, scalable devices, the REI needs to be embedded in a non-interacting host material, preferably one that can be integrated with silicon. In this paper, we show that Er 3+ can be isovalently incorporated into epitaxial Y 2 O 3 thin films on Si (111). We report on the synthesis of epitaxial, single-crystalline Er:Y 2 O 3 on Si with a narrow inhomogeneous linewidth in the photoluminescence spectra, 5.1 GHz (<100 mK) and an optical excited state lifetime of 8.1 ms. The choice of Y 2 O 3 was driven by its low nuclear spin and small lattice mismatch with Si. Using photoluminescence (PL) and electron paramagnetic resonance, we show that Er 3+ substitutes for Y in the crystal lattice. The role of interfacial SiO x , diffusion of silicon into the film, and the effect of buffer layers on inhomogeneous PL linewidth are examined. We also find that the linewidth decreased monotonically with film thickness but surprisingly exhibits no correlation with the film crystalline quality as measured by the x-ray rocking curve scans suggesting other factors at play that limit the inhomogeneous broadening in Y 2 O 3 films.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Spin Decoherence Dynamics of Er 3+ in CeO 2 Films

Developing telecom-compatible spin-photon interfaces is essential towards scalable quantum networks. Erbium ions (Er 3+ ) exhibit a unique combination of a telecom (1.5 mu m) optical transition and an effective spin-1=2 ground state, but identifying a host that enables heterogeneous device integration while preserving long optical and spin coherence remains an open challenge. In this work, we explore the potential of Er 3+ :CeO 2 films on silicon and study the Er 3+ spin coherence, offering low nuclear spin density and the potential for on-chip integration. We demonstrate a 38.8 mu s spin coherence, which can be extended to 176.4 mu s with dynamical decoupling. Pairing experiments with cluster correlation expansion calculations, we identify spectral diffusion induced by bath Er 3+ spin flip-flops as the dominant decoherence mechanism and provide pathways to millisecond-scale coherence.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Pseudospin versus magnetic dipole moment ordering in the isosceles triangular lattice material K 3 Er(VO 4 ) 2

Spin- 1 / 2 antiferromagnetic triangular lattice models are paradigms of geometrical frustration, revealing very different ground states and quantum effects depending on the nature of anisotropies in the model. Due to strong spin orbit coupling and crystal field effects, rare-earth ions can form pseudospin- 1 / 2 magnetic moments with anisotropic single-ion and exchange properties. Thus, rare-earth-based triangular lattices enable the exploration of this interplay between frustration and anisotropy. Here we study one such case, the rare-earth double vanadate glaserite material K 3 Er ( VO 4 ) 2 , which is a quasi-two-dimensional (2D) isosceles triangular antiferromagnet. Our specific heat and neutron powder diffraction data from K 3 Er ( VO 4 ) 2 reveal a transition to long range magnetic order at T N = 155 ± 5 mK which accounts for all R ln 2 entropy. Furthermore, we observe what appears to be a coexistence of three-dimensional (3D) and quasi-2D order below T N . The quasi-2D order leads to an anisotropic Warren-like peak profile for ( h k 0 ) reflections, while the 3D order is best-described by layers of antiferromagnetic b -aligned moments alternating with layers of zero moment. Our magnetic susceptibility data reveal that Er 3 + takes on a strong X Y single-ion anisotropy in K 3 Er ( VO 4 ) 2 , leading to vanishing moments when pseudospins are oriented along c . Thus, the magnetic structure, when considered from the pseudospin point of view could comprise of alternating layers of b -axis and c -axis aligned antiferromagnetism.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Comparing Pr 3+ and Nd 3+ for deactivating the Er 3+ : 4 I 13/2 level in lanthanum titanate glass

Erbium lanthanum titanate glasses were prepared by levitation melting for the spectroscopic study of ways to promote the mid-infrared fluorescence. Two series of heavily erbium doped glasses (15 wt%) were prepared with the addition of either Pr 3+ or Nd 3+ in amounts relative to Er 3+ of 0.05, 0.1, and 0.2. Both ions quench the lower Er 3+ laser level with the Pr 3+ doing so more rapidly. Although high co-dopant concentrations result in higher energy transfer, as clearly evidenced in upconversion and downconversion fluorescence measurements, the mid-infrared lifetime also suffers a reduction and, therefore, a balance must be struck in the co-dopant concentration. Lifetime and spectral measurements indicate that, at a fixed relative co-dopant amount, Pr 3+ is more effective than Nd 3+ at removing the bottleneck of the Er 3+ 4 I 13/2 level. Moreover, consideration of the lifetimes alongside the absorption data of the individual ions indicates that despite the large absorption cross-section of Nd 3+ at 808 nm, the concentration needed to yield more absorbed power than utilizing direct 976 nm excitation of Er 3+ results in unfavorable lifetimes of the mid-infrared transition. In the end, Pr 3+ prevails as the superior co-dopant in terms of the effects on fluorescence lifetimes as well as potential laser system design considerations. In a unique self-doping approach, a reducing melt atmosphere of Ar instead of O 2 creates a small fraction of Ti 3+ . In 5Er 2 O 3 -12La 2 O 3 -83TiO 2 glass, the presence of Ti 3+ quenches the 4 I 13/2 emission about 2.6 times more than the 4 I 11/2 when lifetimes are compared to an O 2 melt environment. As an additional means of increasing the mid-infrared emission, the effect of temperature on the mid- and near- infrared lifetimes of a lightly doped lanthanum titanate composition is investigated between 77-300 K. The mid-infrared lifetime increases by ∼30% while the near-infrared lifetime increases by ∼10%, which suggests in addition to co-doping, active cooling of the gain media will further enhance performance.

Materials Science↗
DOE OSTI2020

Materials Data on Er(AlGe)2 by Materials Project

Al2ErGe2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Er is bonded to six equivalent Ge atoms to form distorted ErGe6 octahedra that share corners with twelve equivalent AlGe4 tetrahedra, edges with six equivalent ErGe6 octahedra, and edges with six equivalent AlGe4 tetrahedra. All Er–Ge bond lengths are 2.98 Å. Al is bonded to four equivalent Ge atoms to form distorted AlGe4 tetrahedra that share corners with six equivalent ErGe6 octahedra, corners with six equivalent AlGe4 tetrahedra, edges with three equivalent ErGe6 octahedra, and edges with three equivalent AlGe4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–56°. There are three shorter (2.55 Å) and one longer (2.57 Å) Al–Ge bond lengths. Ge is bonded to three equivalent Er and four equivalent Al atoms to form a mixture of distorted corner and edge-sharing GeEr3Al4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(IO3)3 by Materials Project

Er(IO3)3 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of one Er(IO3)3 sheet oriented in the (-1, 0, 2) direction. Er3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Er–O bond distances ranging from 2.28–2.41 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Er3+ and one I5+ atom. The O–I bond length is 1.85 Å. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Er3+ and one I5+ atom. The O–I bond length is 1.85 Å. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one I5+ atom. The O–I bond length is 1.86 Å. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Er3+ and one I5+ atom. The O–I bond length is 1.84 Å. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Er3+ and one I5+ atom. The O–I bond length is 1.86 Å. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one I5+ atom. The O–I bond length is 1.84 Å. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Er3+ and one I5+ atom. The O–I bond length is 1.82 Å. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to one Er3+ and one I5+ atom. The O–I bond length is 1.84 Å. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Er3+ and one I5+ atom. The O–I bond length is 1.84 Å. There are three inequivalent I5+ sites. In the first I5+ site, I5+ is bonded in a 5-coordinate geometry to three O2- atoms. In the second I5+ site, I5+ is bonded in a 3-coordinate geometry to three O2- atoms. In the third I5+ site, I5+ is bonded in a 6-coordinate geometry to three O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(MnGe)2 by Materials Project

ErMn2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Er is bonded in a 8-coordinate geometry to eight equivalent Ge atoms. All Er–Ge bond lengths are 3.05 Å. Mn is bonded to four equivalent Ge atoms to form a mixture of edge and corner-sharing MnGe4 tetrahedra. All Mn–Ge bond lengths are 2.43 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Er, four equivalent Mn, and one Ge atom. The Ge–Ge bond length is 2.56 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(BiO2)3 by Materials Project

Er(BiO2)3 is Ilmenite-like structured and crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Er–O bond lengths are 2.27 Å. In the second Er3+ site, Er3+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Er–O bond lengths are 2.26 Å. Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.22–2.63 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to one Er3+ and three equivalent Bi3+ atoms to form a mixture of distorted edge and corner-sharing OErBi3 trigonal pyramids. In the second O2- site, O2- is bonded to one Er3+ and three equivalent Bi3+ atoms to form a mixture of distorted edge and corner-sharing OErBi3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(ReO4)2 by Materials Project

Er(ReO4)2 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Er(ReO4)2 sheet oriented in the (0, 0, 1) direction. Er3+ is bonded to six O2- atoms to form ErO6 octahedra that share corners with six equivalent ReO4 tetrahedra. There are three shorter (2.23 Å) and three longer (2.24 Å) Er–O bond lengths. Re+6.50+ is bonded to four O2- atoms to form ReO4 tetrahedra that share corners with three equivalent ErO6 octahedra. The corner-sharing octahedra tilt angles range from 19–20°. There is one shorter (1.75 Å) and three longer (1.78 Å) Re–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Er3+ and one Re+6.50+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Er3+ and one Re+6.50+ atom. The O–Re bond length is 1.78 Å. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Er3+ and one Re+6.50+ atom. The O–Re bond length is 1.78 Å. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Re+6.50+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one Re+6.50+ atom. The O–Re bond length is 1.75 Å. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Er3+ and one Re+6.50+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Er3+ and one Re+6.50+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Er3+ and one Re+6.50+ atom. The O–Re bond length is 1.78 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er(Ni2P)2 by Materials Project

ErNi4P2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Er is bonded in a 6-coordinate geometry to six equivalent P atoms. There are two shorter (2.80 Å) and four longer (2.83 Å) Er–P bond lengths. Ni is bonded in a 3-coordinate geometry to three equivalent P atoms. There are two shorter (2.30 Å) and one longer (2.31 Å) Ni–P bond lengths. P is bonded in a 9-coordinate geometry to three equivalent Er and six equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

MODFLOW6 models used to evaluate potential stresses and hydrologic conditions driving water-level fluctuations in well ER-5-3-2, Frenchman Flat, Southern Nevada

The hydrograph for well ER-5-3-2 in Frenchman Flat, southern Nevada, has previously unexplained water-level fluctuations. Four, three-dimensional, groundwater models (MODFLOW 6) were developed to evaluate potential stresses and hydrologic conditions affecting the well ER-5-3-2 hydrograph. Four model scenarios were developed that simulated: (1) wellbore leakage without recharge, (2) wellbore leakage with recharge, (3) shallow (low transmissivity) and deep (high transmissivity) carbonate rocks, and (4) lateral heterogeneity of carbonate rocks. Input and output files for the four model scenarios are in the model and output directories, respectively. Hydraulic conductivity, specific storage, and wellbore-leakage rates (when simulated) were estimated with parameter estimation (PEST) by minimizing a weighted composite, sum-of-squares objective function. The objective function was informed by measurement and Tikhonov regularization observations. Measurement observations included drawdowns from the constant-rate aquifer test and water-level altitudes measured in well ER-5-3-2 from 2001-2021. Tikhonov regularization informed hydraulic conductivity and specific storage parameters that were insensitive to measurement observations, where homogeneity was the preferred relation. Batch files, executables, and MODFLOW 6, PEST, and post-processing utilities are in the ancillary directory. Supplementary data also are included in the ancillary directory, including site information, high-frequency water-level and aquifer-test data, transmissivity estimates, water-chemistry data, and water-temperature analyses. This USGS data release contains data, analyses, and model files for the simulations and analysis results described in U.S. Geological Survey Scientific Investigations Report (https://doi.org/10.3133/sir20225132).

54 ENVIRONMENTAL SCIENCES↗