Electronic Structure and Magnetism in the Layered Triangular Lattice Compound CeAuAl${}_4$Ge${}_2$

Abstract

Results are reported for the $f$-electron intermetallic CeAuAl${}_4$Ge${}_2$, where the atomic arrangement of the cerium ions creates the conditions for geometric frustration. Despite this, magnetic susceptibility measurements reveal that the low temperature magnetic exchange interaction is weak, resulting in marginally frustrated behavior and ordering near $T_{\mathrm{M}}$ $\approx$ 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 when the experimentally observed antiferromagnetic exchange interaction and the on-$f$-site Coulomb repulsion (Hubbard) U are considered, the $f$-electron bands 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${}_2$ provides a starting point for investigating geometric magnetic frustration in a cerium lattice without strong Kondo hybridization, where calculations provide useful guidance.

8 pages, 8 figures

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Cited by in corpus (6)

• Magnetic Ordering in GdAuAl${}_4$Ge${}_2$ and TbAuAl${}_4$Ge${}_2$: layered compounds with triangular lanthanide nets
• Magnetic phase diagram and multiple field-induced states in the intermetallic triangular-lattice antiferromagnet NdAuAl${}_4$Ge${}_2$ with Ising-like spins
• Field-Induced Magnetic States in the Metallic Rare-Earth Layered Triangular Antiferromagnet TbAuAl${}_4$Ge${}_2$
• Topological Antiferromagnetic Semimetal for Spintronics: A Case Study of a Layered Square Net System EuZnSb${}_2$
• Metallic layered materials with magnetic frustration: An ARPES view of the SmAuAl${}_4$Ge${}_2$ and TbAuAl${}_4$Ge${}_2$
• Spiral magnetism and chiral superconductivity in Kondo-Hubbard triangular lattice model