Synthesis and characterization of the novel breathing pyrochlore compound Ba3Tm2Zn5O11

In this study, a novel material from the rare-earth based breathing pyrochlore family, Ba3Tm2Zn5O11, was successfully synthesized. Powder X-ray diffraction and high-resolution powder neutron diffraction confirmed phase purity and crystal structure, while thermogravimetric analysis revealed incongruent melting behavior compared to its counterpart, Ba3Yb2Zn5O11. High-quality single crystals of Ba3Tm2Zn5O11 were grown using the traveling solvent floating zone technique and assessed using Laue diffractometer and single crystal X-ray diffraction. Thermodynamic characterization indicated paramagnetic behavior down to 0.05 K, and inelastic neutron scattering measurements identified distinct crystal electric field bands. Additional low-energy excitation studies on single crystals revealed dispersionless bands at 0.8 and 1 meV. Computed phonon dispersions from first principles calculations ruled out phonons as the source of these modes, further illustrating the puzzling and unique properties of Ba3Tm2Zn5O11.

在这项研究中，成功合成了一种来自稀土基呼吸烧绿石家族的新型材料Ba₃Tm₂Zn₅O₁₁。粉末X射线衍射和高分辨率粉末中子衍射证实了相纯度和晶体结构，而热重分析显示其与同类材料Ba₃Yb₂Zn₅O₁₁相比具有不一致的熔化行为。使用移动溶剂浮区技术生长了高质量的Ba₃Tm₂Zn₅O₁₁单晶，并使用劳厄衍射仪和单晶X射线衍射进行了评估。热力学特性表明在低至0.05 K时具有顺磁行为，非弹性中子散射测量确定了不同的晶体电场能带。对单晶进行的额外低能激发研究揭示了在0.8和1 meV处的无弥散能带。基于第一性原理计算得到的声子色散排除了声子是这些模式的来源，进一步说明了Ba₃Tm₂Zn₅O₁₁令人困惑且独特的性质。