Manipulating Cu vacancy in Yb triangular lattice Materials: Investigating the quantum disordered compound CuYbSe₂ and spin glass Cu_2.73⁢YbP₂

Journal Article · Tue Aug 12 00:00:00 EDT 2025 · Physical Review Materials

DOI:https://doi.org/10.1103/m33y-7fjb· OSTI ID:2584492

Xing, Jie ^[1]; Liurukara, Duminda S. ^[1]; Feng, Erxi ^[1]; Cao, Huibo ^[1]

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1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Yb-based triangular lattice materials have attracted significant attention due to their potential for hosting exotic magnetic quantum states. In this paper, we report the structural, magnetic, and thermodynamic properties of two Yb triangular lattice compounds with vacancy disorder at nonmagnetic Cu sites: CuYbSe₂ and Cu_2.73⁢YbP₂. Single-crystal x-ray diffraction determines notable Cu-site vacancies in both materials. Unlike a single Cu site with 0.5 occupancy in CuYbSe₂, Cu_2.73⁢YbP₂ only presents 27% vacancies on one of three Cu sites. Magnetic susceptibility measurements indicate dominant antiferromagnetic interactions between Yb³⁺ ions. The effective magnetic moment is consistent with an effective spin-1/2 state of Yb³⁺. CuYbSe₂ exhibits strong magnetic anisotropy between in-plane and out-of-plane directions with the estimated exchange interactions 𝐽_𝑎/𝑘_B= 6.48 K and 𝐽_𝑐/𝑘_B= 2.55 K. No magnetic ordering is observed down to 0.4 K, supporting its quantum disordered ground state and candidacy as a quantum spin liquid. In contrast, Cu_2.73⁢YbP₂ shows clear evidence of spin freezing at 4.5 K in both magnetization and heat capacity data, indicating a spin glass state. The field-induced magnetic orders are found in CuYbSe₂. These results highlight the critical role of structural vacancies in perturbing Yb-based triangular lattices. In conclusion, we demonstrate that while the intrinsic Yb triangular lattices are comparable, the presence of Cu vacancies can fundamentally alter the magnetic ground state—tuning the system between quantum disordered and spin glass behavior.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 2584492
• Journal Information: Physical Review Materials, Journal Name: Physical Review Materials Journal Issue: 8 Vol. 9; ISSN 2475-9953
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

Frustrated magnetism
Magnetic phase transitions
Magnetic susceptibility
Magnetism
Specific heat