Angle-resolved photoemission spectroscopy study of rare-earth tritelluride charge density wave compounds: RTe3 (R = Pr, Er)

The electronic structures of layered rare-earth tritelluride RTe3 (R = Pr, Er) charge density wave (CDW) compounds have been investigated by performing R 4d→4f resonant photoemission spectroscopy (RPES) and angle-resolved photoemission spectroscopy (ARPES) measurements for high-quality single crystals. R 4d→4f RPES measurements reveal that the R 4f states do not contribute directly to the CDWformation in RTe3 but that the R 4f-Te 5p hybridization in PrTe3 is significantly larger than that in ErTe3. In the photon-energy maps for the Fermi-edge (EF)-crossing states in RTe3, straight vertical dispersions are observed along kc, demonstrating the 2D character for the near-EF states in both R = Pr and Er. This finding implies the weak interlayer interaction between R-Te(1) and Te(2)-Te(3) layers, which is supported by the similar linear dichroism in ARPES for PrTe3 and ErTe3. The CDW-induced Fermi surface of PrTe3 exhibits two-fold symmetric features while that of ErTe3 exhibits four-fold symmetric features. This finding reveals different CDWdistortions in PrTe3 and ErTe3, the origin of which is likely to be different ionic sizes of R ions and different R 4f-Te 5p hybridization.