Lu/Se Substitution Effect on Magnetic Properties of Yb-Based Zigzag Chain Semiconductor YbCuS2

Summary

The study investigates the effects of Lu and Se substitutions on the magnetic properties of YbCuS2, a zigzag chain semiconductor. The results show that both substitutions decrease the antiferromagnetic transition temperature TN, but the Se substitution leads to a larger lattice expansion. The gapless quasiparticle excitations are robust against the chemical substitutions.

Highlights

• Lu and Se substitutions decrease the antiferromagnetic transition temperature TN in YbCuS2.
• Se substitution leads to a larger lattice expansion compared to Lu substitution.
• Gapless quasiparticle excitations are observed in both substituted systems.
• The value of 1/T1T increases with the substitutions.
• The substitutions weaken the first-order characteristics of the phase transition.
• The results indicate a clear relationship between the magnetic ordered states and quasiparticle excitations.
• The study provides a constraint on theoretical models for the origin of the gapless excitations.

Key Insights

• The Lu and Se substitutions have different effects on the lattice constants, with Se substitution leading to a significant expansion, while Lu substitution results in minimal changes. This suggests that the Se substitution corresponds to a negative pressure effect, while the Lu substitution simply dilutes the magnetic Yb3+ ions.
• The decrease in TN due to the substitutions can be attributed to the reduction and inhomogeneity in the inter-chain coupling J3, leading to a decrease and distribution in TN.
• The gapless quasiparticle excitations are robust against the chemical substitutions, suggesting that their origin is related to the intra-chain interactions, which contribute to quantum fluctuations.
• The increase in 1/T1T with the substitutions can be attributed to the enhancement of fluctuations due to the decrease in TN, making the system closer to the quantum critical point.
• The substitutions weaken the first-order characteristics of the phase transition, indicating that the chemical substitutions have a different effect on the phase transition compared to pressure.
• The study highlights the importance of considering the effects of chemical substitutions on the lattice constants and the inter-chain coupling in understanding the magnetic properties of YbCuS2.
• The results provide a constraint on theoretical models for the origin of the gapless excitations, suggesting that the nematic particle may be a possible explanation, but the impurity effect on the nematic particle remains unclear.

Mindmap

Citation

Hori, F., Matsudaira, H., Kitagawa, S., Ishida, K., Mizutani, S., Shirai, H., & Onimaru, T. (2024). Lu/Se Substitution Effect on Magnetic Properties of Yb-Based Zigzag Chain Semiconductor YbCuS2 (Version 1). arXiv. https://doi.org/10.48550/ARXIV.2412.18373