Optical study on intermediate-valence compounds Yb1?x Lux Al3

• 来源期刊: 中国物理B（英文版）
• 关键词: heavy fermions intermediate valence system optical conductivity hybridization effect
• 年，卷（期）: 2018,（1）
• 页码范围: 209-214
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/1/017803

摘要

We report an optical spectroscopy study on intermediate valence system Yb1?x Lux Al3 with x=0, 0.25, 0.5, 0.75, and 1. The Kondo temperature in the system is known to increase with increasing Lu concentration. Therefore, it is expected that the energy scale of the hybridization gap should increase with increasing Lu concentration based on the periodic Anderson model. On the contrary, we find that the spectral structure associated with the hybridization effect shifts monotonically to lower energy. Furthermore, the Lu substitution results in a substantial increase of the free carrier spectral weight and less pronounced plasma frequency reduction upon lowering temperature. We attribute the effect to the disruption of the Kondo lattice periodicity by the random substitution of Yb by Lu. The work highlights the importance of the lattice periodicity of the rare earth element for understanding the Kondo lattice phenomena.