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Sr2Pt8−xAs: a layered incommensurately modulated metal with saturated resistivity

Authors :
Sergiy Katrych
Edoardo Martino
Kimberly Modic
Philip J. W. Moll
Gabriel Autès
Alla Arakcheeva
Oleg V. Yazyev
Toni Helm
Maja D. Bachmann
Andrea Pisoni
László Forró
Source :
IUCrJ, Vol 5, Iss 4, Pp 470-477 (2018)
Publication Year :
2018
Publisher :
International Union of Crystallography, 2018.

Abstract

The high-pressure synthesis and incommensurately modulated structure are reported for the new compound Sr2Pt8−x As, with x = 0.715 (5). The structure consists of Sr2Pt3As 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.

Details

Language :
English
ISSN :
20522525
Volume :
5
Issue :
4
Database :
OpenAIRE
Journal :
IUCrJ
Accession number :
edsair.doi.dedup.....e4e02a83b5370ceb5f83e5870da9db81