Self-doping processes between planesand chains in themetal-to-superconductor transition ofYBa2Cu3O6.9
2014 (English)In: Scientific Reports, ISSN 2045-2322, Vol. 4, no 07017Article in journal (Refereed) Published
The interplay between the quasi 1-dimensional CuO-chains and the 2-dimensional CuO2 planes ofYBa2Cu3O61x (YBCO) has been in focus for a long time. Although the CuO-chains are known to beimportant as charge reservoirs that enable superconductivity for a range of oxygen doping levels in YBCO,the understanding of the dynamics of its temperature-driven metal-superconductor transition (MST)remains a challenge. We present a combined study using x-ray absorption spectroscopy and resonantinelastic x-ray scattering (RIXS) revealing how a reconstruction of the apical O(4)-derived interplanarorbitals during theMSTof optimally dopedYBCOleads to substantial hole-transfer from the chains into theplanes, i.e. self-doping. Our ionic model calculations show that localized divalent charge-transferconfigurations are expected to be abundant in the chains of YBCO. While these indeed appear in the RIXSspectra from YBCO in the normal, metallic, state, they are largely suppressed in the superconducting stateand, instead, signatures of Cu trivalent charge-transfer configurations in the planes become enhanced. Inthe quest for understanding the fundamental mechanism for high-Tc-superconductivity (HTSC) inperovskite cuprate materials, the observation of such an interplanar self-doping process in YBCO opens aunique novel channel for studying the dynamics of HTSC.
Place, publisher, year, edition, pages
Nature Publishing Group, 2014. Vol. 4, no 07017
Superconductor YBCO XAS RIXS spectroscopy synchrotron radiation superconductivity
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:liu:diva-111968DOI: 10.1038/srep07017ISI: 000344760700007PubMedID: 25388860OAI: oai:DiVA.org:liu-111968DiVA: diva2:762664