Anomalous band renormalization due to high energy $kink$ in the colossal thermoelectric material K$_{0.65}$RhO$_2$

Susmita Changdar; G. Shipunov; N. B. Joseph; N. C. Plumb; M. Shi; B. Büchner; Awadhesh Narayan; S. Aswartham; S. Thirupathaiah

doi:10.1103/PhysRevMaterials.5.055402

paper

Anomalous band renormalization due to high energy $k ink$ in the colossal thermoelectric material K $_{0.65}$ RhO $_{2}$

arXiv:2007.02016 · doi:10.1103/PhysRevMaterials.5.055402

Abstract

We report on low-energy electronic structure and electronic correlations of K $_{0.65}$ RhO $_{2}$ , studied using high-resolution angle-resolved photoemission spectroscopy (ARPES) technique and density functional theory (DFT) calculations. We observe a highly correlated hole pocket on the Fermi surface. We further notice that the correlations are momentum dependent. Most importantly, two $k ink s$ at binding energies of 75 meV and 195 meV have been observed from the band dispersion in the vicinity of the Fermi level. While the low energy $k ink$ at 75 meV can be understood as a result of the electron-phonon interaction, the presence of high energy $k ink$ at 195 meV is totally a new discovery of this system leading to an anomalous band renormalization. Based on systematic analysis of our experimental data, we propose high frequency bosonic excitations as a plausible origin of the high energy anomaly. Further, we notice that the high energy anomaly has important implications in obtaining the colossal thermoelectric power of K $_{0.65}$ RhO $_{2}$ .

20 pages, 8 figures

Anomalous band renormalization due to high energy kink in the colossal thermoelectric material K0.65​RhO2​

Abstract

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Anomalous band renormalization due to high energy $k ink$ in the colossal thermoelectric material K $_{0.65}$ RhO $_{2}$