Theoretical investigations on the α-LiAlO2 properties via first-principles calculation

Ma, Shenggui; Gao, Tao; Li, Shichang; Xi-jun, MA; Shen, Yanhong; Lu, Tiecheng

doi:10.1016/j.fusengdes.2016.05.021

Cited by 14 publications

(11 citation statements)

References 33 publications

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“…Detailed information on lattice dynamical properties of crystal materials can be obtained from the phonon band structures. Phonon vibrational frequencies will contribute to phase stability and phase transformation of the crystal structural . According to the standard group theoretical irreducible representation analysis, Raman active modes and infrared active modes of predicted phases of PuH x ( x = 1–10) are clearly assigned (see Tables S2 and S3) at selected pressures.…”

Section: Resultsmentioning

confidence: 99%

Phase Diagram and Bonding States of Pu–H Binary Compounds at High Pressures

Zhao

et al. 2020

J. Phys. Chem. C

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The high-pressure processes of plutonium hydrides are usually involved in many practical situations, such as the volume expansion during the hydride formation, the pressure of helium bubbles due to the decay of plutonium, and the stress due to the formation of the oxide film. These cases could lead to the high-pressure phase transition of plutonium hydrides and thereby affect the properties of the material. The crystal structure and bonding properties of plutonium hydrides (PuH 1−10 ) under atmospheric pressure and high pressure are investigated by using the first-principle method in combination with a structure searching technique. Our results show that the predicted lattice structures of plutonium hydrides are stable over the given pressure range. A novel stable stoichiometry, PuH with space groupFm3̅ m, is thermodynamically, dynamically, and mechanically stable in the pressure range of 62−188 GPa, which may be synthesized through the pressure-induced disproportionation of PuH 2 . In particular, our theoretically predicted results indicate that PuH 3 undergoes pressure-induced phase transitions with the following sequence of phases, P6 3 cm → Pnma → R3̅ m → Cmcm, and the corresponding transition pressures are computed to be 4, 76, and 150 GPa, respectively. Interestingly, the most striking feature of PuH 3 is the pressure-induced transition from insulating to metallic forms. Analysis of the electric structures, charge density differences, and electronic localization functions indicates that all phases act mainly as metallic with ionic bonding at high pressure.

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Section: Resultsmentioning

confidence: 99%

Phase Diagram and Bonding States of Pu–H Binary Compounds at High Pressures

Zhao

et al. 2020

J. Phys. Chem. C

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“…The ever-increasing demand for energy generated, initiated further research into alternate methods of renewable energy production and storage methodologies for the power production. In that respect, Li-based ceramics are technologically important and considered by the community for applications ranging from nuclear fusion to batteries [1][2][3][4][5][6][7][8]. LiAlO 2 , a lithium based ceramic material, has been considered with the prospect of being used as a tritium breeder material in magnetic confined nuclear fusion reactors after promising initial research regarding the physical and thermodynamic properties of the material as well as the potential tritium breeding ratio (TBR) [8,9].…”

Section: Introductionmentioning

confidence: 99%

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

et al. 2019

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Lithium aluminate, LiAlO 2 , is a material that is presently being considered as a tritium breeder material in fusion reactors and coating material in Li-conducting electrodes. Here, we employ atomistic simulation techniques to show that the lowest energy intrinsic defect process is the cation anti-site defect (1.10 eV per defect). This was followed closely by the lithium Frenkel defect (1.44 eV per defect), which ensures a high lithium content in the material and inclination for lithium diffusion from formation of vacancies. Li self-diffusion is three dimensional and exhibits a curved pathway with a migration barrier of 0.53 eV. We considered a variety of dopants with charges +1 (Na, K and Rb), +2 (Mg, Ca, Sr and Ba), +3 (Ga, Fe, Co, Ni, Mn, Sc, Y and La) and +4 (Si, Ge, Ti, Zr and Ce) on the Al site. Dopants Mg 2+ and Ge 4+ can facilitate the formation of Li interstitials and Li vacancies, respectively. Trivalent dopants Fe 3+ , Ni 3+ and Mn 3+ prefer to occupy the Al site with exoergic solution energies meaning that they are candidate dopants for the synthesis of Li (Al, M) O 2 (M = Fe, Ni and Mn) compounds.Energies 2019, 12, 2895 2 of 10 Computational MethodsThe present computational study was based on classical pair-wise potential calculations to describe LiAlO 2 via the General Utility Lattice Program (GULP) code [23,24]. In the present approach, the total energy (lattice energy) is determined by long range (i.e., Coulombic) and short range [i.e., electron-electron repulsive and attractive intermolecular forces (van der Waals forces)]. The latter were modelled using Buckingham potentials (refer to the supplementary information). The van der Waals forces arising from the spontaneous formation of instantaneous dipoles are very important as the formation energy results are sensitive to those forces. The present modelling approach takes into the account of Van der Waals forces as a function of the interatomic distance (r) [23,24]. Two-body Buckingham potential mentioned in the supplementary information consists of two parts. The first part of the equation represents the Pauli repulsion (electron-electron) and the second part denotes the van der Waals interaction. Ionic positions and lattice parameters were relaxed using the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm [24]. Convergence criteria dictated that in relaxed configurations, forces on each atom was <0.001 eV/Å. To introduce point defects in the lattice we used the Mott-Littleton methodology [25] similarly to recent work [26][27][28]. It is established that although the present methodology may overestimate the defect formation enthalpies at the dilute limit, the trends will be unchanged [29]. In a thermodynamic perspective defect parameters can be described by comparing the real (i.e., defective) crystal to an isobaric or isochoric ideal (i.e., non-defective) crystal. Defect formation parameters can be interconnected through thermodynamic relations [30,31], with the present atomistic simulations corresponding to the isobaric parameters for the mig...

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“…LiAlO 2 is a ceramic material that is known to occur in at least five crystal structures: rhombohedral α-LiAlO 2 (space group R3m) [1], orthorhombic β-LiAlO 2 (space group Pna2 1 ) [2], tetragonal γ-LiAlO 2 (space group P4 1 2 1 2) [3], and tetragonal δ-LiAlO 2 (space group I4 1 /amd) [4,5]. Among these, both β and γ forms are tetrahedrally coordinated while α and δ are octahedrally coordinated.…”

Section: Introductionmentioning

confidence: 99%

“…The γ → δ phase transition has been studied experimentally [4,5], and Sailuam et al [20] have carried out a firstprinciples computational study of the band structures and pressure-induced γ → δ phase transition [20]. Ma et al have done a first-principles study of α-LiAlO 2 [1]. However, a comprehensive computational treatment of the electronic and structural properties of LiAlO 2 appears to remain missing in the literature.…”

Section: Introductionmentioning

confidence: 99%

Quasiparticle self-consistent $GW$ band structures and phase transitions of LiAlO$_2$ in tetrahedrally and octahedrally coordinated structures

Popp¹,

Lambrecht²

2022

Preprint

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A first-principles computational study is presented of various phases of LiAlO2. The relative total energies and equations of state of the α, β and γ phases are determined after structural relaxation of each phase. The β and γ tetrahedral phases are found to be very close in energy and lattice volume with the γ phase having the lowest energy. The octahedral α phase is a high-pressure phase and the transition pressure from the γ and β phases to α is determined to be about 1 GPa. The electronic band structures of each phase at their own equilibrium volume are determined using the quasiparticle self-consistent (QS) GW method as well as using the 0.8Σ approach in which the QSGW self-energy is reduced by a factor 0.8 to correct for the underscreening of W in QSGW . The effective masses of the band edges and the nature of the band gaps are presented. The lowest energy γ phase is found to have a pseudodirect gap of 7.69 eV. The gap is direct at Γ but corresponds to a dipole forbidden transition. The imaginary part of the dielectric function and the absorption coefficient are calculated in the long-wavelength limit and the random phase approximation, without local field or electron-hole interaction effects for each phase and their anisotropies are discussed. Si doping on the Al site is investigated as a possible n-type dopant in γ-LiAlO2 using a 128 atom supercell corresponding to 3.125 % Si on the Al sublattice in the generalized gradient approximation and a smaller 16 atom cell with 25 % Si in the QSGW approximation. The Si is found to significantly perturb the conduction band and lower the gap but a clearly separated deep donor defect level is not found. However, the donor binding energy is still expected to be relatively deep, of order a few 0.1 eV in the hydrogenic effective mass approximation.

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Theoretical investigations on the α-LiAlO2 properties via first-principles calculation

Cited by 14 publications

References 33 publications

Phase Diagram and Bonding States of Pu–H Binary Compounds at High Pressures

Phase Diagram and Bonding States of Pu–H Binary Compounds at High Pressures

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

Quasiparticle self-consistent $GW$ band structures and phase transitions of LiAlO$_2$ in tetrahedrally and octahedrally coordinated structures

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