Divacancy superstructures in thermoelectric calcium-doped sodium cobaltate. / Porter, Dan; Roger, M.; Gutmann, M. J.; Sivaperumal, Uthay; Prabhakaran, D.; Boothroyd, A. T.; Pandiyan, Manoj; Goff, Jon.

In: Physical Review B, Vol. 90, 054101, 04.08.2014.

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Abstract

We have grown single crystals of NaxCayCoO2 and determined their superstructures as a function of composition using neutron and x-ray diffraction. Inclusion of Ca2+ stabilizes a single superstructure across a wide range of temperatures and concentrations. The superstructure in the Na+ layers is based on arrays of divacancy clusters with Ca2+ ions occupying the central site, and it has an ideal concentration Na4/7Ca1/7CoO2. Previous measurements of the thermoelectric properties on this system are discussed in light of this superstructure. Na4/7Ca1/7CoO2 corresponds to the maximum in thermoelectric performance of this system.
Original languageEnglish
Article number054101
JournalPhysical Review B
Volume90
DOIs
Publication statusPublished - 4 Aug 2014
This open access research output is licenced under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

ID: 22616459