Temperature activated electron transport in CaMnO3

Goldyreva, Ekaterina I.; Леонидов, И. А.; Патракеев, М.В.; Кожевников, В. Л.

doi:10.1016/j.ssi.2013.12.022

Cited by 11 publications

(5 citation statements)

References 31 publications

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“…There are contradictory data reported in literature concerning TE [15][16][17][18], bulk [19], and structural [9,12,13,[20][21][22] characteristics of these compounds. For example, it was reported that the absolute values of Seebeck coefficient, S, decrease with increasing temperature for pure CaMnO 3 ; however, bismuth-doped compounds exhibit the opposite trend with a maximum |S|-value equals to 350 µVK -1 at room temperature [15,18]. Other studies report on values as great as |S|=500 µVK -1 for pure CaMnO 3 at temperatures as low as 50 K [16], where others report on increasing |S|-values with the temperature for both pure and rare-earth doped compounds [17].…”

Section: A N U S C R I P Tmentioning

confidence: 94%

Structural stability of calcium-manganate based CaO(CaMnO3)m (m = 1, 2, 3, ∞) compounds for thermoelectric applications

Baranovskiy

Amouyal

2016

Journal of Alloys and Compounds

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Section: A N U S C R I P Tmentioning

confidence: 94%

Structural stability of calcium-manganate based CaO(CaMnO3)m (m = 1, 2, 3, ∞) compounds for thermoelectric applications

Baranovskiy

Amouyal

2016

Journal of Alloys and Compounds

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“…Reports on TMOs are available for many systems, such as CaMnO 3 , (Eu,Ba)TiO 3 , (La,Pb)MnO 3 , (La,Sr,Ag)MnO 3 , Ca 4 Mn 3 O 10 , LaMnO 3 , (La,Ca)MnO 3 , LaCrO 3 , (Ca/Sr/Pb,Bi)MnO 3 , (Sr,La)FeO 4 , (Pr,Ca,Sr)MnO 3 , (Ca,Nd/Pr/Sm)MnO 3 , (Sm,Ca)MnO 3 , TiO 2 , BaCoS 2 , La 2‐x Sr x NiO 4 , CeO 2 , (Ca,Gd)(Mn,Nb)O 3 , (Ca,Yb/Lu)(Mn,Nb)O 3 , (Bi/La/Mo,Ca)MnO 3 , and Fe 1‐x Zn x Cr 2 S 4 . These compounds exhibit fascinatingly rich physics originating from intricate electron‐electron and electron‐phonon interactions, e. g. double exchange and superexchange interactions, and Jahn‐Teller distortions .…”

Section: Introductionmentioning

confidence: 99%

“…The pre‐exponential factor entails, among other terms, the on‐site Coulomb repulsion . Distinction between the cases where the hopping nature is either adiabatic or non‐adiabatic based solely on the temperature dependence of electrical conductivity is rather difficult, so that complementary evaluations such as spin ordering and electron transfer integrals are required …”

Section: Introductionmentioning

confidence: 99%

Evaluation of Polaron Transport in Solids from First‐principles

Natanzon

Azulay

Amouyal

2020

Israel Journal of Chemistry

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Polarons are formed in polar or ionic solids, either molecular or crystalline, due to local distortions of the lattice induced by charge carriers. Polaron hopping is the primary mechanism of charge transport in these materials, such as functional ceramic compounds, with applications in photovoltaics, thermoelectrics, two-dimensional electron gas transistors, magnetic sensors, spin valve devices, and memories. Understanding the fundamental physics of polaron hopping is, therefore, of prime technological importance. This article provides a brief physical background of polarons and their hopping mechanism, focusing on first-principles calculations of polaron properties. Herein, we review recent selected studies applying the density functional theory (DFT), and describe the merits and challenges in applying DFT for such calculations, highlighting the need to address both electronic and vibrational aspects. The vibrational component of the polaron is evaluated based on structural and total energy calculations, whereas the electronic component is derived from both total energy and electron density calculations. To address the most compelling challenge of calculating polaron properties using DFT, which is the issue of electron localization, we propose to employ calculations of selected vibrational properties, such as the sound velocity, shear modulus, and Grüneisen parameter, to represent the polaron hopping energy; all of which originate from the stiffness of inter-atomic bonds. Such methodology is expected to be more straightforward than the existing ones, however demands standardization. Keywords: charge transport • polaron hopping • first-principles calculations • oxides • vibrational properties nism dominating the transport correlates to the Debye temperature, θ D. At low temperatures, where T < θ D /2, tunneling predominates, whereas at higher temperatures hopping is more probable. Reports on TMOs are available for many systems, such as CaMnO 3 , [4-10] (

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“…A possible explanation for these differences can be found by taking oxygen deficiency into consideration. Goldyreva et al [42,43] report that oxygen vacancies act as electron donors by creating Mn 3? from Mn 4?…”

Section: Thermoelectric Propertiesmentioning

confidence: 99%

Formation mechanism and thermoelectric properties of CaMnO3 thin films synthesized by annealing of Ca0.5Mn0.5O films

et al. 2019

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A two-step synthesis approach was utilized to grow CaMnO 3 on M-, R-and C-plane sapphire substrates. Radio-frequency reactive magnetron sputtering was used to grow rock-salt-structured (Ca, Mn)O followed by a 3-h annealing step at 800°C in oxygen flow to form the distorted perovskite phase CaMnO 3. The effect of temperature in the post-annealing step was investigated using x-ray diffraction. The phase transformation to CaMnO 3 started at 450°C and was completed at 550°C. Films grown on R-and C-plane sapphire showed similar structure with a mixed orientation, whereas the film grown on M-plane sapphire was epitaxially grown with an out-of-plane orientation in the [202] direction. The thermoelectric characterization showed that the film grown on M-plane sapphire has about 3.5 times lower resistivity compared to the other films with a resistivity of 0.077 Xcm at 500°C. The difference in resistivity is a result from difference in crystal structure, single orientation for M-plane sapphire compared to mixed for R-and C-plane sapphire. The highest absolute Seebeck coefficient value is-350 lV K-1 for all films and is decreasing with temperature.

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Temperature activated electron transport in CaMnO3

Cited by 11 publications

References 31 publications

Structural stability of calcium-manganate based CaO(CaMnO3)m (m = 1, 2, 3, ∞) compounds for thermoelectric applications

Structural stability of calcium-manganate based CaO(CaMnO3)m (m = 1, 2, 3, ∞) compounds for thermoelectric applications

Evaluation of Polaron Transport in Solids from First‐principles

Formation mechanism and thermoelectric properties of CaMnO3 thin films synthesized by annealing of Ca0.5Mn0.5O films

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