Enhanced Seebeck coefficient by a filling-induced Lifshitz transition in KxRhO2

Abstract

We have systematically measured the transport properties in the layered rhodium oxide K${}_x$RhO${}_2$ single crystals ($0.5\lesssim x\lesssim 0.67$), which is isostructural to the thermoelectric oxide Na${}_x$CoO${}_2$. We find that below $x=0.64$ the Seebeck coefficient is anomalously enhanced at low temperatures with increasing $x$, while it is proportional to the temperature like a conventional metal above $x=0.65$, suggesting an existence of a critical content $x^{\ast }\simeq 0.65$. For the origin of this anomalous behavior, we discuss a filling-induced Lifshitz transition, which is characterized by a sudden topological change in the cylindrical hole Fermi surfaces at the critical content $x^{\ast }$.

5 pages, 5 figures, to be published in Phys. Rev. B

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Cited by in corpus (2)

• Manifestation of the thermoelectric properties in Ge-based halide perovskites
• Correlation in transport coefficients of hole-doped CuRhO${}_2$ single crystals