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arXiv · 1901.02116

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

Naoko Ito·Mayu Ishii·Ryuji Okazaki
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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 $x^{*} \simeq 0.65$. 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 $x^*$.

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Naoko Ito, Mayu Ishii, Ryuji Okazaki. 2019-01-08. Enhanced Seebeck coefficient by a filling-induced Lifshitz transition in KxRhO2. https://doi.org/10.1103/physrevb.99.041112

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