First-principles study on the structural, elastic, and electronic properties of γ-LiAlO2

Wu, Shunqing; Hou, Zhufeng; Zhu, Zhaowu

doi:10.1016/j.commatsci.2009.02.028

Cited by 26 publications

(9 citation statements)

References 24 publications

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“…The g ii of γ-LiAlO 2 are all positive and in the same order of magnitude, thus indicating a 3-dimensional network of bonds dominated by Coulomb interactions. This is compatible with the analyses of Wu et al 10 using DFT calculations, where the Al-O bonding exhibits a covalent contribution, whereas the Li-O bonding is predominantly ionic.…”

Section: Samplesupporting

confidence: 92%

Single-crystal elastic and thermodynamic properties of γ-LiAlO2

Haussühl

Bayarjargal

Ruiz‐Fuertes

2021

Journal of Applied Physics

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The elastic properties of γ-LiAlO2 were reinvestigated with the aid of resonant ultrasound spectroscopy (RUS) at ambient conditions. A strong discrepancy of the elastic coefficients derived by RUS can be found from the experimental results from literature, where c12 and c13 deviate from our results by about 15 % (24 GPa) and 60 % (42 GPa), respectively. In contrast to the experimental cij from literature we can recognize a good agreement between the elastic coefficients derived from RUS and the values using density functional theory (DFT). The dielectric permittivity was measured on large plane-parellel plates and the piezoelectric stress coefficient e123 = 0.14 C m −2 was derived from RUS measurements at ambient conditions. The heat capacity between 4 K -398 K has been obtained by microcalorimetry using a relaxation calorimeter. The Debye temperature was derived from heat capacity measurements (ΘCp = 676 K) and from RUS measurements (Θ elastic = 688 K).

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Section: Samplesupporting

confidence: 92%

Single-crystal elastic and thermodynamic properties of γ-LiAlO2

Haussühl

Bayarjargal

Ruiz‐Fuertes

2021

Journal of Applied Physics

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“…With these parameters, we obtained relaxed lattice constants a ¼ 5:139 # A and c ¼ 6:244 # A for the equilibrium structure of Li 4 Al 4 O 8 . Note that our calculated lattice constants are very similar to other available GGA estimates (a ¼ 5:223 # A and c ¼ 6:309 # A) 14) and experimental values (a ¼ 5:17 # A and c ¼ 6:27 # A). 15) The band structure for Li 4 Al 4 O 8 was then calculated by using the equilibrium atomic structure, which yields a direct gap of 4.86 eV.…”

supporting

confidence: 89%

“…Reciprocal space integrations of the bulk GaN, LAO, and GaN(1 " 100)/LAO(100) heterostructures were carried out using 100, 30, and 15 irreducible k points generated from 9 Â 9 Â 7, 6 Â 5 Â 5, and 6 Â 5 Â 1 Monkhorst-Pack girds in the first Brillouin zone to achieve a force accuracy of 0.0001 eV/ # A, respectively. With these parameters, we obtained relaxed lattice constants a 14) On the other hand, artificial compressed strain should be imposed on the GaN side of the GaN(1 " 100)/LAO(100) interface because, in reality, the subsequently deposited GaN film is compressed to match the dimensions of the LAO template. We calculate the bulk unit cell of Ga 2 N 2 of fixed dimensions of a ¼ 3:122 # A and c ¼ 5:139 # A originating from growth on lattice-mismatched LAO, which in turn determines a direct gap of 2.25 eV.…”

mentioning

confidence: 99%

Valence-Band Offset ofm-Plane GaN(11̄00) Films Grown on LiAlO₂(100) Substrates

Liu¹,

Chou²,

Hong³

2013

Appl. Phys. Express

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We present first-principles calculations on the heterojunction between a wurtzite GaN(1 100) film and a tetragonal LiAlO 2 (100) substrate. The relative barrier heights of different models of the GaNð1 100Þ k LiAlO 2 ð100Þ interface are examined as a function of the valence-band offset. The most favorable interface consists of fourfold-coordinated N and Ga, which has the lowest valence-band offset of 0.534 eV. This interface structure indicates that the nitrided LiAlO 2 (100) surface stabilizes the GaN/LiAlO 2 heteroepitaxial structures. Our findings explain a variety of experiments and may prove useful for improving the internal quantum efficiency of nonpolar GaN-based optoelectronic devices.A mong the alternative substrates for GaN epitaxy, the tetragonal lithium aluminum oxide (space group P4 1 2 1 2, -LiAlO 2 , LAO) was regarded as one of the most closely lattice-matched substrates. The epitaxial formation of a wurtzite m-plane GaN(1 " 100) film on a tetragonal LAO(100) substrate, i.e., GaNð1 "100Þ k LAOð100Þ, is nearly lattice matched and confirms that the lattice mismatches between wurtzite GaN and tetragonal LAO are 0.3% for GaN½0001 k LAO½010 and 1.7% for GaN½11 " 20 k LAO½001. 1-4) These small lattice mismatches suggest that LAO is a promising substrate material for the epitaxial growth of the hexagonal GaN thin film. In addition, the fabrication of m-plane GaN(1 " 100) film, i.e., the growth of GaN films oriented along nonpolar directions, has shown the promising potential for improving the internal quantum efficiency of GaN-based multiple-quantum-well (MQW) light-emitting diodes (LEDs) due to the absence of polarization-related electrostatic fields. 4) However, the nature of the atomic bonding between GaN epilayers and LAO templates has not been elucidated yet. The bonding configurations or electronic properties of heterojunctions can be characterized on the basis of the valence-or conductionband discontinuities. In this paper, we calculate the valenceband offset (VBO) of the optimized GaN(1 " 100)/LAO(100) heterostructure to elucidate the bonding configuration that enables strain relaxation and analyze the electronic charge density. The VBO using the standard bulk-plus-lineup procedure can be split into two terms as follows: 5,6)

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“…The ␣-LiAlO 2 has a larger value with 254.8 GPa than ␥-LiAlO 2 with 131.9 GPa of Young's modulus [32] indicating that ␣-LiAlO 2 is stiffer than ␥-LiAlO 2 .…”

Section: Mechanical Propertiesmentioning

confidence: 91%

“…The critical value which separates ductility and brittleness is about 1.75. The calculated results show that ␣-LiAlO 2 is brittle with B/G equal 1.40, while the ␥-LiAlO 2 is ductile with B/G equal 1.79 [32].…”

Section: Mechanical Propertiesmentioning

confidence: 93%

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

Gao

et al. 2016

Fusion Engineering and Design

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First-principles study on the structural, elastic, and electronic properties of γ-LiAlO2

Cited by 26 publications

References 24 publications

Single-crystal elastic and thermodynamic properties of γ-LiAlO2

Single-crystal elastic and thermodynamic properties of γ-LiAlO2

Valence-Band Offset ofm-Plane GaN(11̄00) Films Grown on LiAlO₂(100) Substrates

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

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First-principles study on the structural, elastic, and electronic properties of γ-LiAlO2

Cited by 26 publications

References 24 publications

Single-crystal elastic and thermodynamic properties of γ-LiAlO2

Single-crystal elastic and thermodynamic properties of γ-LiAlO2

Valence-Band Offset ofm-Plane GaN(11̄00) Films Grown on LiAlO2(100) Substrates

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

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Valence-Band Offset ofm-Plane GaN(11̄00) Films Grown on LiAlO₂(100) Substrates