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Sr 2 Pt 8− x As: a layered incommensurately modulated metal with saturated resistivity

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Martino Edoardo, Arakcheeva Alla, Autès Gabriel, Pisoni Andrea, Bachmann Maja D., Modic Kimberly A., Helm Toni, Yazyev Oleg V., Moll Philip J. W., Forró László, Katrych Sergiy, Martino Edoardo, Arakcheeva Alla, Autès Gabriel, Pisoni Andrea, Bachmann Maja D., Modic Kimberly A., Helm Toni, Yazyev Oleg V., Moll Philip J. W., Forró László, Katrych Sergiy, Martino Edoardo, Arakcheeva Alla, et al. ,
Project Mott Physics Beyond the Heisenberg Model in Iridates and Related Materials
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Original article (peer-reviewed)

Journal IUCrJ
Volume (Issue) 5(4)
Page(s) 470 - 477
Title of proceedings IUCrJ
DOI 10.1107/s2052252518007303

Open Access

URL http://doi.org/10.1107/S2052252518007303
Type of Open Access Publisher (Gold Open Access)

Abstract

The high-pressure synthesis and incommensurately modulated structure are reported for the new compound Sr 2 Pt 8− x As, with x = 0.715 (5). The structure consists of Sr 2 Pt 3 As layers alternating with Pt-only corrugated grids. Ab initio calculations predict a metallic character with a dominant role of the Pt d electrons. The electrical resistivity (ρ) and Seebeck coefficient confirm the metallic character, but surprisingly, ρ showed a near-flat temperature dependence. This observation fits the description of the Mooij correlation for electrical resistivity in disordered metals, originally developed for statistically distributed point defects. The discussed material has a long-range crystallographic order, but the high concentration of Pt vacancies, incommensurately ordered, strongly influences the electronic conduction properties. This result extends the range of validity of the Mooij correlation to long-range ordered incommensurately modulated vacancies. Motivated by the layered structure, the resistivity anisotropy was measured in a focused-ion-beam micro-fabricated well oriented single crystal. A low resistivity anisotropy indicates that the layers are electrically coupled and conduction channels along different directions are intermixed.
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