Synthesis and transport properties of La2NiO4

Zhou, Nan; Chen, G.; Zhang, H.J.; Zhou, Chang

doi:10.1016/j.physb.2009.07.186

Cited by 25 publications

(19 citation statements)

References 21 publications

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“…According to our calculations, experiments showing thermopower oscillating with temperature (with a maximum at intermediate temperatures) have been obtained analyzing samples in that doping region (hole doped, nonstoichiometric, even if some of them do not explicitly mention the oxygen content). [52][53][54] However, an accurate placement of the maximum in the Seebeck coefficient as a function of temperature is not given by our calculations, with that type of agreement being similar to what has been found in other correlated oxides. 49 Zhou et al 52 have shown a slight increase in S at high temperature experimentally, but the exact δ value of their samples is not provided; from our calculations, we can argue that those samples would have a substantial δ value on the order of δ ∼ 0.15-0.2.…”

Section: Vca Calculationssupporting

confidence: 53%

“…[52][53][54] However, an accurate placement of the maximum in the Seebeck coefficient as a function of temperature is not given by our calculations, with that type of agreement being similar to what has been found in other correlated oxides. 49 Zhou et al 52 have shown a slight increase in S at high temperature experimentally, but the exact δ value of their samples is not provided; from our calculations, we can argue that those samples would have a substantial δ value on the order of δ ∼ 0.15-0.2. The best quantitative agreement between our calculations and those reported from experiments at low-doping levels can be obtained with the TB-mBJLDA functional.…”

Section: Vca Calculationssupporting

confidence: 53%

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Enhanced thermoelectric response of hole-doped La2NiO4+δfromab initiocalculations

2012

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Thermoelectric properties of the system La 2 NiO 4+δ have been studied ab initio. Large Seebeck coefficient values are predicted for the parent compound, and to some extent remain in the hole-doped metallic phase, accompanied by an increase in the conductivity. This system, due to its layered structure, would be a suitable candidate for an improvement of its thermoelectric figure of merit by nanostructurization in thin films, which has already been shown to increase the electrical conductivity (σ ). Our calculations show that in the region around La 2 NiO 4.05 , the system has a large thermopower at high temperatures and also a substantially increased σ . Films grown with this low-doping concentration will show an optimal relationship between thermopower and σ . This result is obtained for various exchange-correlation schemes (correlated, uncorrelated, and parameter free) that we use to analyze the electronic structure of the hole-doped compound.

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Section: Vca Calculationssupporting

confidence: 53%

Section: Vca Calculationssupporting

confidence: 53%

Enhanced thermoelectric response of hole-doped La2NiO4+δfromab initiocalculations

2012

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“…[4] and references therein for the phenomenology with hole doping). However to our surprise, while there are standard-DFT [13,61], DFT+U [62] and meta generalizedgradient approximation [63] studies, we could not find an in-depth realistic-DMFT investigation for this material in the literature. This section is hence also devoted to fill this void.…”

Section: La 2 Niomentioning

confidence: 61%

Assessing the correlated electronic structure of lanthanum nickelates

Lechermann

2021

Preprint

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The series of nickel-oxide compounds LaNiO 3 (formal Ni(d 7 )), La 2 NiO 4 (formal Ni(d 8 )) and LaNiO 2 (formal Ni(d 9 )) is investigated by firstprinciples many-body, using a combination of density functional theory, selfinteraction correction and dynamical mean-field theory. The characteristics of these different nickelates, in good agreement with available experimental data, is revealed by employing a compound-independent choice for the local Coulomb interactions. The dichotomy within the low-energy dominant Ni-eg sector of {d z 2 , d x 2 −y 2 } kind is rising with growing Ni(3d) filling across the series. An intermediate-coupling scheme for spin-polarized calculations is introduced, which leads to very weak Ni ordered moments for the infinite-layer compound LaNiO 2 in contrast to the robust-moment system La 2 NiO 4 .

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“…Oxygen transport mechanism in first homologues of R-P phases was modeled by such methods as molecular dynamics (MD) [25][26][27][28][29][30][31][32] and density functional theory (DFT) calculations [23,30,[32][33][34][35][36][37][38][39][40]. The dominating mechanism of oxygen transport in K 2 NiF 4 -like compounds is socalled cooperative mechanism (being also referred to as interstitialcy mechanism [30], cooperative interstitialcy mechanism [31] or interstitialcy-mediated mechanism [36]) as mentioned above involving lattice oxygen of perovskite layers and highly mobile interstitial oxygen of rock salt layers with the second one being able to be accumulated in a large amount [23,30,31,36,38,39,41,42].…”

Section: Introductionmentioning

confidence: 99%

Oxygen transport in Pr nickelates: Elucidation of atomic-scale features

et al. 2020

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Pr 2 NiO 4+δ oxide with a layered Ruddlesden-Popper structure is a promising material for SOFC cathodes and oxygen separation membranes due to a high oxygen mobility provided by the cooperative mechanism of oxygen migration involving both interstitial oxygen species and apical oxygen of the NiO 6 octahedra. Doping by Ca improves thermodynamic stability and increases electronic conductivity of Pr 2−x Ca x NiO 4+δ , but decreases oxygen mobility due to decreasing the oxygen excess and appearing of 1-2 additional slow diffusion channels at x ≥ 0.4, probably, due to hampering of cooperative mechanism of migration. However, atomic-scale features of these materials determining oxygen migration require further studies. In this work characteristics of oxygen diffusion in Pr 2−x Ca x NiO 4+δ (x = 0-0.6) are compared with results of the surface analysis by X-ray photoelectron spectroscopy and modeling of the interstitial oxygen migration by the plane-wave density functional theory calculations. According to the X-ray photoelectron spectroscopy data, the surface is enriched by Pr for undoped sample and by Ca for doped ones. The O1s peak at~531 eV corresponding to a weakly bound form of surface oxygen located at Pr cations disappears at~500°C. Migration of interstitial oxygen was modeled for a I4/mmm phase of Pr 2 NiO 4+δ . The interstitial oxygen anion repulses the apical one in the NiO 6 octahedra pushing it into the tetrahedral site between Pr cations. The calculated activation barrier of this migration is equal to 0.585 eV, which reasonably agrees with the experimental value of 0.83 eV obtained by the oxygen isotope exchange method. At the same time, for the model compound Ca 2 NiO 4+δ , obtained by isomorphic substitution of Pr by Ca in Pr 2 NiO 4+δ , calculations implied formation of the peroxide ion comprised of interstitial and lattice oxygen species not revealed in the case of incomplete substitution (up to PrCaNiO 4+δ composition).Hence, calculations in the framework of the plane-wave density functional theory provide a realistic estimation of specificity of oxygen migration features in Pr 2 NiO 4+δ doped by alkaline-earth metals.

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Synthesis and transport properties of La2NiO4

Cited by 25 publications

References 21 publications

Enhanced thermoelectric response of hole-doped La2NiO4+δfromab initiocalculations

Enhanced thermoelectric response of hole-doped La2NiO4+δfromab initiocalculations

Assessing the correlated electronic structure of lanthanum nickelates

Oxygen transport in Pr nickelates: Elucidation of atomic-scale features

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