Mixed Valence and Superconductivity in Perovskite Antimonates

Kim, Minu; Klenner, Steffen; McNally, Graham; Nuß, Jürgen; Yaresko, A. N.; Wedig, Ulrich; Kremer, Reinhard K.; Pöttgen, Rainer; Takagi, H.

doi:10.1021/acs.chemmater.1c01362

Cited by 17 publications

(11 citation statements)

References 43 publications

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“…3 ). We also note that a clear signature of charge disproportionation of Sb 3+ and Sb 5+ has been observed very recently in 121 Sb Mössbauer spectroscopy in BSO 43 . No such clear spectroscopic signature of Bi 3+ and Bi 5+ has been reported in BBO which can be attributed to the predominant oxygen holes 24 – 26 .…”

Section: Mainsupporting

confidence: 73%

Superconductivity in (Ba,K)SbO3

et al. 2022

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Abstract(Ba,K)BiO3 constitute an interesting class of superconductors, where the remarkably high superconducting transition temperature Tc of 30 K arises in proximity to charge density wave order. However, the precise mechanism behind these phases remains unclear. Here, enabled by high-pressure synthesis, we report superconductivity in (Ba,K)SbO3 with a positive oxygen–metal charge transfer energy in contrast to (Ba,K)BiO3. The parent compound BaSbO3−δ shows a larger charge density wave gap compared to BaBiO3. As the charge density wave order is suppressed via potassium substitution up to 65%, superconductivity emerges, rising up to Tc = 15 K. This value is lower than the maximum Tc of (Ba,K)BiO3, but higher by more than a factor of two at comparable potassium concentrations. The discovery of an enhanced charge density wave gap and superconductivity in (Ba,K)SbO3 indicates that strong oxygen–metal covalency may be more essential than the sign of the charge transfer energy in the main-group perovskite superconductors.

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Section: Mainsupporting

confidence: 73%

Superconductivity in (Ba,K)SbO3

et al. 2022

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“…where f (ε) and D (ε) are the Fermi-Dirac function and the number of orbitals per unit energy range, respectively. e total number of electrons, N, inside a sphere of radius, k, is given by [23] N � v…”

Section: Electronic Heat Capacitymentioning

confidence: 99%

Thermal and Electronic Conductivity in Normal and Superconducting Erbium Nickel Borocarbide (ErNi2B2C)

Tesfaye

2022

Advances in Materials Science and Engineering

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In this work, the total electronic energy, the electronic thermal conductivity, and the heat capacity of erbium nickel borocarbide, ErNi2B2C, in the normal and superconducting states are calculated using Boltzmann transport equations (BTEs) and energy dispersion relation function. Results from the electronic thermal conductivity versus temperature (T) are presented. From the result, electrical and thermal conductivity at low temperature obey the Wiedemann–Franz law. Moreover, at the normal state, the electronic thermal conductivity of ErNi2B2C is directly proportional to the temperature (T) and reaches its maximum (kink) at the transition temperature, Tc. After the superconducting transition temperature, the electronic thermal conductivity begin to decrease. The drop in electronic thermal conductivity beyond its peak (kink) value is due to the formation of energy gap and the absence of Cooper pairs.

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“…The valence skipping effect and negative-U effect of Sb ion has been focused in (Ba,K)SbO 3 (BKSO) which is a similar material to BKBO, because BKSO shows a superconductivity with a maximum T c of 15 K [61,62].…”

Section: Candidate Materialsmentioning

confidence: 99%

Valence skipping phenomena, charge Kondo effect, and superconductivity

2022

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We review a recent progress of a superconductivity and a charge Kondo effect mediated by valence skippers which are elements skipping the valence state. To understand the valence skipping phenomenon, we introduce a negative-U effect phenomenologically, and we show an origin of the negative-U effect, a superconductivity and charge Kondo effect based on the negative-U effect. We also show a new mechanism in which the valence skipping phenomenon and charge Kondo effect are understood unifiedly by the pair hopping interaction. As an experimental progress, we review a charge Kondo effect and a superconductivity discovered in Tl-doped PbTe. Especially, we focus on a drastic increase of the inverse of the relaxation time (1/T1) observed around the Kondo temperature by the nuclear magnetic resonance experiment, and we suggest a possible theoretical scenario on the basis of the effective model with the pair hopping interaction. Finally, we discuss the related materials, and describe the perspective of valence skipping phenomenon.

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Mixed Valence and Superconductivity in Perovskite Antimonates

Cited by 17 publications

References 43 publications

Superconductivity in (Ba,K)SbO3

Superconductivity in (Ba,K)SbO3

Thermal and Electronic Conductivity in Normal and Superconducting Erbium Nickel Borocarbide (ErNi2B2C)

Valence skipping phenomena, charge Kondo effect, and superconductivity

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