Electronic Structures of the Charge Density Wave System RTe$_{2}$ (R$=$Ce, Pr) investigated by ARPES

The rare-earth (R)-based RTe$_{2}$ compounds are known as the charge-density-wave (CDW) systems. In this work, we have investigated the electronic structures of RTe$_{2}$ (R$=$Ce, Pr) by employing angle-resolved photoemission spectroscopy (ARPES) experiment and the first-principles band structure calculations. The overall shapes and sizes of the measured Fermi surfaces (FSs) of RTe$_{2}$ are found to be similar to those of the calculated FSs for the undistorted structures. The metallic states crossing the Fermi level (E$_{\mathrm{F}})$ are observed in ARPES even in the CDW state, indicating that the metallic states remain under the CDW transition with the remnant ungapped FSs. R 4$f$ PES spectra exhibit that the 4$f$ hybridization peak (4$f^{\mathrm{n}}c^{\mathrm{m-1}})$ in R$=$Pr is located deeper than in R$=$Ce, resulting in the much weaker 4$f$ spectral intensity near E$_{\mathrm{F}}$ in R$=$Pr. The shadow bands and the corresponding very weak FSs are found to arise from the band folding due to the interaction of Te(1) layers with R-Te(2) layers and the CDW-induced FS reconstruction. The E$_{\mathrm{F}}$-crossing states are stronger with the linear vertical polarization than with the linear horizontal polarization. The photon-energy maps in ARPES demonstrate the two-dimensional character of the near- E$_{\mathrm{F}}$ states.