Discovery of Superconductivity in (Ba,K)SbO${}_3$

Abstract

Superconducting bismuthates (Ba,K)BiO${}_3$ (BKBO) constitute an interesting class of superconductors in that superconductivity with a remarkably high $T_{\mathrm{c}}$ of 30 K arises in proximity to charge density wave (CDW) order. Prior understanding on the driving mechanism of the CDW and superconductivity emphasizes the role of either bismuth (negative $U$ model) or oxygen ions (ligand hole model). While holes in BKBO presumably reside on oxygen owing to their negative charge transfer energy, so far there has been no other comparative material studied. Here, we introduce (Ba,K)SbO${}_3$ (BKSO) in which the Sb 5$s$ orbital energy is higher than that of the Bi 6$s$ orbitals enabling tuning of the charge transfer energy from negative to slightly positive. The parent compound BaSbO${}_{3-\delta }$ shows a larger CDW gap compared to the undoped bismuthate BaBiO${}_3$. As the CDW order is suppressed via potassium substitution up to 65 %, superconductivity emerges, rising up to $T_{\mathrm{c}}$ = 15 K. This value is lower than the maximum $T_{\mathrm{c}}$ of BKBO, but higher by more than a factor of two at comparable potassium concentrations. The discovery of an enhanced CDW gap and superconductivity in BKSO indicates that the sign of the charge transfer energy may not be crucial, but instead strong metal-oxygen covalency plays the essential role in constituting a CDW and high-$T_{\mathrm{c}}$ superconductivity in the main-group perovskite oxides.

References in corpus (5)

• Electron-Phonon Coupling from $\text{Ab Initio}$ Linear-Response Theory within the $GW$ Method: Correlation-Enhanced Interactions and Superconductivity in Ba${}_{1-x}$K${}_x$BiO${}_3$
• Hybridization effects and bond-disproportionation in the bismuth perovskites
• Fcc breathing instability in BaBiO_3 from first principles
• Model of the electron-phonon interaction and optical conductivity of Ba${}_{1-x}$K${}_x$BiO${}_3$ superconductors
• Holes' character and bond versus charge disproportionation in $s-p$ $AB{X}_3$ perovskites

Cited by in corpus (14)

• Orbital hybridization-driven charge density wave transition in CsV3Sb5 kagome superconductor
• A hybrid Monte Carlo study of bond-stretching electron-phonon interactions and charge order in BaBiO${}_3$
• Advances in Complex Oxide Quantum Materials Through New Approaches to Molecular Beam Epitaxy
• Charge Transfer and $dd$ excitations in AgF${}_2$
• Local inversion-symmetry breaking in a bismuthate high-$T_c$ superconductor
• Intersite Coulomb Interactions in Charge Ordered Systems
• Diffuse Scattering from Correlated Electron Systems
• Charge ordering as the driving mechanism for superconductivity in rare-earth nickel oxides
• Charting the landscape of Bardeen-Cooper-Schrieffer superconductors in experimentally known compounds
• Atomic and Electronic Structures of Correlated SrRuO3/SrTiO3 Superlattices
• Electron-phonon mediated superconductivity in La${}_6$Ni${}_5$O${}_{12}$ nickel oxides
• Designing Non-Relativistic Spin Splitting in Oxide Perovskites
• Persistence of small polarons into the superconducting phase of Ba${}_{1-x}$K${}_x$BiO${}_3$
• Real-space orbital tiling approach for the design of novel superconductors