Squeezing clathrate cages to host trivalent rare-earth guests

Program Document · Wed Nov 01 04:00:00 EDT 2017

OSTI ID:1429688

Wang, Jian ^[1]; He, Yuping ^[2]; Mordvinova, Natalia E. ^[3]; Lebedev, Oleg ^[3]; Kovnir, Kirill ^[1]

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1. Iowa State Univ., Ames, IA (United States). Department of Chemistry; Ames Lab., Ames, IA (United States)
2. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
3. Laboratoire CRISMAT, ENSICAEN, CNRS UMR (France)

Strike difference of the trivalent rare-earth cations from their alkali and alkaline-earth peers is in the presence of localized 4f-electrons and strong spin-orbit coupling. Placing trivalent rare-earth cations inside the fullerene molecules or in between the blocks of itinerant magnetic intermetallics gave rise to plethora of fascinating properties and materials. A long-time missing but hardly desired piece is the semiconducting or metallic compound where rare-earth cations are situated inside the oversized polyhedral cages of three-dimensional framework. In this work we present a synthesis of such compounds, rare-earth containing clathrates Ba_8-xR_xCu₁₆P₃₀. The unambiguous proofs of their composition and crystal structure were achieved by a combination of synchrotron powder diffraction, time-of-flight neutron powder diffraction, scanning-transmission electron microscopy, and electron energy-loss spectroscopy. Our quantum-mechanical calculations and experimental characterizations show that the incorporation of the rare-earth cations significantly enhances the hole mobility and concentration which results in the drastic increase in the thermoelectric performance.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
• DOE Contract Number: AC04-94AL85000; SC0008931; AC02-06CH11357; NA0003525
• OSTI ID: 1429688
• Report Number(s): SAND--2017-12413J; 658738
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY