Thermopower enhancement by encapsulating cerium in clathrate cages

Abstract

The increasing worldwide energy consumption calls for the design of more efficient energy systems. Thermoelectrics could be used to convert waste heat back to useful electric energy if only more efficient materials were available. The ideal thermoelectric material combines high electrical conductivity and thermopower with low thermal conductivity. In this regard, the intermetallic type-I clathrates show promise with their exceedingly low lattice thermal conductivities [1]. Here we report the successful incorporation of cerium as guest atom into the clathrate crystal structure. In many simpler intermetallic compounds, this rare earth element is known to lead, via the Kondo interaction, to strong correlation phenomena including the ocurrence of giant thermopowers at low temperatures [2]. Indeed, we observe a 50% enhancement of the thermopower compared to a rare earth-free reference material. Importantly, this enhancement occurs at high temperatures and we suggest that a `rattling' enhanced Kondo interaction [3] underlies this effect.

arXiv comment6 pages, 4 figures

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Cited by in corpus (5)

• Quantum phases driven by strong correlations
• Influence of phonon-assisted tunneling on the linear thermoelectric transport through molecular quantum dots
• Anomalous thermal conductivity in 2D silica nanocages of immobilizing noble gas atom
• Synthesis and transport properties of ternary type-I Si clathrate K8Al7Si39
• Size effect on the thermal conductivity of a type-I clathrate