Abstract
The electronic structure of a charge density wave (CDW) system PrTe3 and its modulated structure in the CDW phase have been investigated by employing ARPES, XAS, Pr 4 f RPES, and first-principles band structure calculation. Pr ions are found to be nearly trivalent, supporting the CDW instability in the metallic Te sheets through partial filling. Finite Pr 4 f spectral weight is observed near the Fermi level, suggesting the non-negligible Pr 4 f contribution to the CDW formation through the Pr 4 f -Te 5p hybridization. The two-fold symmetric features in the measured Fermi surface (FS) of PrTe3 are explained by the calculated FS for the assumed 7 × 1 CDW supercell formation in Te sheets. The shadow bands and the corresponding very weak FSs are observed, which originate from both the band folding due to the 3D interaction of Te sheets with neighboring Pr-Te layers and that due to the CDW-induced FS reconstruction. The straight vertical FSs are observed along kz, demonstrating the nearly 2D character for the near-EF states. The observed linear dichroism reveals the in-plane orbital character of the near-EF Te 5p states.
Highlights
The charge density wave (CDW) transition is one of the most interesting phase transitions, which occurs due to the Fermi surface (FS) instability[1,2], like the Peierls transition in one dimension (1D)[3]
Supercell formation, have not been sorted out yet. We have addressed these questions by performing careful measurements of angle-resolved photoemission spectroscopy (ARPES), Pr 4d → 4 f resonant photoemission spectroscopy (RPES), and soft X-ray absorption spectroscopy (XAS) for high-quality stoichiometric single crystal of PrTe3, and first-principles electronic structure calculations and tight-binding (TB) model calculations for the CDW supercell structure
The electronic structure of PrTe3 has been investigated by employing ARPES, XAS, RPES, and first-principles band structure calculation, and the questions addressed in Introduction are answered
Summary
Metallic, which are distorted by the the Peierls-like mechanism, as investigated by Papoian and Hoffmann[37]. New features are observed near the (0, ±1) points in the FS for the 7 × 1 structure, while gaps open at (±1, 0), resulting in the mirror symmetry, in contrast to the non-CDW FS of PrTe3 (see Fig. S1(b) for the calculated non-CDW FS map.) Remarkably good agreement is found between the calculated FS for the assumed 7 × 1 supercell and the measured FS, indicating that the two-fold symmetric FS in PrTe3 arises from the 7 × 1 modulated structure formation in the CDW phase. The effect of the band folding, observed in ARPES, agrees very well with that in the calculations These findings clearly indicates that the modulated structure of PrTe3 in the CDW phase would be close to a 7 × 1 × 1 supercell structure. This idea deserves to be checked more systematically further in future
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