Results are reported for the f -electron intermetallic CeAuAl 4 Ge 2 , where the atomic arrangement of the cerium ions creates the conditions for possible geometric frustration. The magnetic susceptibility follows a Curie-Weiss temperature dependence at elevated temperatures, revealing that the cerium ions are trivalent. At lower temperatures the crystal electric field splits the Hund's rule multiplet, resulting in a weak low-temperature magnetic exchange interaction and ordering near T M ≈ 1.4 K . This occurs within a metallic Kondo lattice, where electrical resistivity and heat capacity measurements show that the Kondo-driven electronic correlations are negligible. Quantum oscillations are detected in ac-magnetic susceptibility measurements and uncover small charge carrier effective masses. Electronic structure calculations reveal that inclusion of an on- f -site Coulomb repulsion (Hubbard) U results in antiferromagnetic order and causes the f -electron bands to move away from the Fermi level, resulting in electronic behavior that is dominated by the s , p , and d bands, which are all characterized by light electron masses. Thus, CeAuAl 4 Ge 2 may provide a starting point for investigating geometric magnetic frustration in a cerium lattice without strong Kondo hybridization, where calculations provide useful guidance.
Physics, Astronomy, and Materials Science
© 2017 American Physical Society
crystal structure, electronic structure, fermi surface, frustrated magnetism, magnetic anisotropy, metals
Zhang, S., N. Aryal, K. Huang, K-W. Chen, Y. Lai, D. Graf, T. Besara, T. Siegrist, E. Manousakis, and R. E. Baumbach. "Electronic structure and magnetism in the layered triangular lattice compound CeAuAl 4 Ge 2." Physical Review Materials 1, no. 4 (2017).
Physical Review Materials