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Electronic structure of the Gd-based intermetallics GdCu2Ge2 and GdCuAl3

M. Pinterić1,2, M. Dressel1, P. Puphal3,*, and M. Wenzel1,†

  • *Contact author: p.puphal@fkf.mpg.de
  • †Contact author: maxim.wenzel@pi1.physik.uni-stuttgart.de
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Phys. Rev. B 114, 175119 – Published 14 September, 2026

DOI: https://doi.org/10.1103/mrpm-nkms

Abstract

We present a temperature-dependent reflectivity study of single crystals of the ternary intermetallic compounds GdCu2Ge2 and GdCuAl3 over a broad spectral range (100–18000cm−1, equivalent to 12 meV–2.23 eV) down to 13 K. Below 2000 cm−1, the optical spectra are dominated by the response of itinerant charge carriers exhibiting two distinct scattering rates. While the response of the highly damped charge carriers shows negligible temperature dependence, the weakly damped carriers closely follow the dc resistivity and are significantly suppressed in GdCuAl3, consistent with its higher resistivity. Supported by density-functional theory calculations, we further show that elemental substitution from GdCu2Ge2 to GdCuAl3 tunes the X-site p-orbital character (X = Ge, Al) of the low-energy electronic structure, while preserving key features such as linearly dispersing bands and saddle points despite the accompanying structural modifications. The reduced experimental plasma frequency of both compounds signals enhanced electronic correlations, which induce moderate band-energy renormalization.

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Phys. Rev. B 114, 175119– Published 14 September, 2026
  • Received 24 March 2026
  • Revised 16 July 2026
  • Accepted 28 August 2026
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