Magnetic Frustration in CuYbSe${}_2$: an Yb-Based Triangular Lattice Selenide

Abstract

The Yb based triangular lattice delafossites $A$Yb$X_2$ ($A$ = alkali metal, $X$ = O, S, Se) have recently been studied as quantum spin liquid candidates. We report the synthesis of powders and single crystals of CuYbSe${}_2$ with a perfect triangular lattice of Yb${}^{3+}$ moments. Magnetic susceptibility and heat capacity measurements reveal no evidence of long-range magnetic ordering down to $1.8$~K in spite of a significant antiferromagnetic exchange between Yb${}^{3+}$ moments, suggesting a frustrated magnetic system. Electrical resistivity measurements indicate insulating behavior, consistent with the localized nature of magnetic moments. Heat capacity reveals that CuYbSe${}_2$ can be treated as an effective spin $S=1/2$ triangular lattice antiferromagnet below $\sim 50$~K. Magnetic susceptibility measurements on single crystals reveals weak magnetic anisotropy. These properties position CuYbSe${}_2$ as a promising candidate for a quantum spin liquid state and as a new platform for exploring exotic magnetic ground states in triangular lattice systems.