Charge disproportionation and Jahn-Teller distortion in LiNiO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>and NaNiO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>: A density functional theory study

Chen, Hungru; Freeman, Colin L.; Harding, John H.

doi:10.1103/physrevb.84.085108

Cited by 71 publications

(63 citation statements)

References 43 publications

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“…Furthermore, the ground state at y = 0.5 had six 2.09 Å Ni-O pairs per each Ni, indicating total removal of the JT distortion. This result is consistent with the absence of any observed JT distortion in stoichiometric LiNiO 2 [16,17], including the bond lengths determined by NMR measurement [19], in contradiction to DFT calculations [7,14,18]. According to the results of this study, Ni 2+ is actively created at finite temperature and suppresses the JT distortion, which explains its non-observation in experiment.…”

Section: Resultssupporting

confidence: 87%

“…For example, the origin and role of Ni-Li exchange (to create Ni-Li antisite pairs), as well as the effects of Co and Al in NCA, are not fully understood [2,[12][13][14][15]. Moreover, experiment has not confirmed the theoretically-predicted Jahn-Teller (JT) distortion in the (rhombohedral) LiNiO 2 [7,14,[16][17][18][19]. Thus, it would also be helpful to clarify the influence of Ni-antisite ions on the JT distortion.…”

Section: Introductionmentioning

confidence: 99%

“…The ideal crystal structure of NC belongs to the 3 space group, with alternating layers of Li and transition metal ions, as illustrated in Figure 1 [7,[16][17][18]22]. To accommodate the atomic degrees of freedom of this system efficiently, we devise a generalized CE that includes the magnetic degrees of freedom explicitly.…”

Section: Introductionmentioning

confidence: 99%

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Rapidly convergent cluster expansion and application to lithium ion battery materials

2017

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The convergence of a cluster expansion for lithium transition metal oxides is improved by explicit treatment of transition metal (TM) magnetic moments. The approach is applied to layered LiCo y Ni 1-y O 2 (NC). The ground state and low-lying excited state structures are identified and the distribution of TM ions and magnetic moment in those structures is investigated to explain the origin of Ni-antisite ions and Jahn-Teller distortion. The developed model also reveals the mechanisms governing the atomic arrangement of NC, including in-plane Co-Co vs. Co-Ni competition, magnetic frustration vs. disproportionation competition, and cationic interactions spanning adjacent layers.2

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Section: Resultssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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Rapidly convergent cluster expansion and application to lithium ion battery materials

2017

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“…[65] A monoclinic primitive cell with C2/m space group was used for LiNiO 2 to allow for the Jahn-Teller distortion of the Ni-O bond. [66] The rotationally invariant scheme by Dudarev et al [67] was used for the Hubbard U correction to GGA (GGA+U). For the TM oxides, the U values from reference [68] were employed (U the PBE correlation energy, α is the mixing parameter and ω is a range-separation parameter.…”

Section: Methodsmentioning

confidence: 99%

Calibrating transition-metal energy levels and oxygen bands in first-principles calculations: Accurate prediction of redox potentials and charge transfer in lithium transition-metal oxides

2015

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Transition metal (TM) oxides play an increasingly important role in technology today including applications such as catalysis, solar energy harvesting, and energy storage. In many of these applications, the details of their electronic structure near the Fermi level are critically important for their properties. We propose a first-principles based computational methodology for the accurate prediction of oxygen charge transfer in TM oxides and lithium TM (Li-TM) oxides. To obtain accurate electronic structures, the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional is adopted and the amount of exact Hartree-Fock exchange (mixing parameter) is adjusted to reproduce reference band gaps.We show that the HSE06 functional with optimal mixing parameter yields not only improved electronic densities of states but also better energetics (Li-intercalation voltages) for LiCoO 2 and LiNiO 2 as compared to GGA, GGA+U and standard HSE06.We find that the optimal mixing parameters for TM oxides are system-specific and correlate with the covalency (ionicity) of the TM species. Strong covalent (ionic) nature of TM-O bonding leads to lower (higher) optimal mixing parameters. We find that optimized HSE06 functionals predict stronger hybridization of the Co 3d and O 2p orbitals than GGA, resulting in a greater contribution from oxygen states to charge compensation upon delithiation in LiCoO 2 . We also find that the band gaps of Li-TM oxides increase linearly with the mixing parameter, enabling the straightforward determination of optimal mixing parameters based on GGA (α = 0.0) and HSE06 (α = 0.25) calculations. Our results also show that G 0 W 0 @GGA+U band gaps of TM oxides (MO, M = Mn, Co, Ni) and LiCoO 2 agree well with experimental references, suggesting that G 0 W 0 calculations can be used as a reference for the calibration of the mixing parameter in case no experimental band gap has been reported. 3

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“…It is important to note that in the metal-insulator transition nickelate NdNiO 3 , the CD is experimentally found to be about 0.4e for the formal charge order 2Ni 3+ → Ni 2+ + Ni 4+ [19,20]. Very similarly, in LiNiO 2 the CD is calculated to be 0.2-0.4e for the formal Ni 2+ + Ni 4+ state [21], i.e. 0.1-0.2e per valence difference of 1.…”

mentioning

confidence: 93%

Charge–spin–orbital states in the tri-layered nickelate La₄Ni₃O₈: an ab initio study

Wu¹

2013

New J. Phys.

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The electronic and magnetic structures of La 4 Ni 3 O 8 , an analogue of the hole doped cuprates, are studied using the configuration state constrained local-spin-density approximation plus Hubbard U calculations. It is found to be a C-type antiferromagnetic Mott insulator, in which an orbital hybridization strongly reduces an otherwise possible charge disproportionation. This state accounts for several experimental observations. The involved Ni 2+ high-spin state and its orbital configuration are found to be against a crystal-field level picture, which predicts an Ni 2+ low-spin state in the NiO 2 square lattice. We note, however, that La 4 Ni 3 O 8 , if in the low-spin state, would be a chargehomogeneous ferromagnetic half-metal with only the up-spin x 2 -y 2 conduction band. Therefore, low-spin nickelates may be explored for any interesting property.

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Charge disproportionation and Jahn-Teller distortion in LiNiO2and NaNiO2: A density functional theory study

Cited by 71 publications

References 43 publications

Rapidly convergent cluster expansion and application to lithium ion battery materials

Rapidly convergent cluster expansion and application to lithium ion battery materials

Calibrating transition-metal energy levels and oxygen bands in first-principles calculations: Accurate prediction of redox potentials and charge transfer in lithium transition-metal oxides

Charge–spin–orbital states in the tri-layered nickelate La₄Ni₃O₈: an ab initio study

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Charge disproportionation and Jahn-Teller distortion in LiNiO2and NaNiO2: A density functional theory study

Cited by 71 publications

References 43 publications

Rapidly convergent cluster expansion and application to lithium ion battery materials

Rapidly convergent cluster expansion and application to lithium ion battery materials

Calibrating transition-metal energy levels and oxygen bands in first-principles calculations: Accurate prediction of redox potentials and charge transfer in lithium transition-metal oxides

Charge–spin–orbital states in the tri-layered nickelate La4Ni3O8: an ab initio study

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Charge–spin–orbital states in the tri-layered nickelate La₄Ni₃O₈: an ab initio study