化学无序诱导的热力学金属性Mo4TGa16Ge（T = Co、Rh或Ir）中的非金属输运
Chemical-Disorder-Induced Non-metallic Transport in Thermodynamically Metallic Mo4TGa16Ge (T = Co, Rh or Ir)
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中文总结 AI 辅助
本研究报道了从超导体Mo4PtGa17衍生的新系列化合物Mo4TGa16Ge，其虽保持金属性电子结构，却因窄带对化学无序的高敏感性而表现出非金属输运行为，为平带材料中无序控制输运提供了可调平台。
中文摘要 AI 辅助
平带电子态可能对化学扰动高度敏感，为探索超越母体材料的更广泛电子行为提供了机会。在此，我们报道了一系列新化合物Mo4TGa16Ge（T = Co、Rh或Ir）的发现，这些化合物通过名义上保持总价电子数不变，从强关联平带超导体Mo4PtGa17衍生而来。所有三种材料均结晶于非中心对称立方空间群F-43m，其中Ge选择性占据母体化合物中一个Ga位点。尽管总电子数保持不变，Mo4TGa16Ge却表现出与Mo4PtGa17显著不同的性质。理论计算预测其具有金属性电子结构，费米能级处存在狭窄且占主导的Mo-d态，而低温热容结果表明有限索末菲系数。然而，电输运测量显示主要为非金属行为，且观测到较小的激活能，排除了传统半导体行为的可能性。结合化学键分析、电子结构以及X射线晶体学和光谱学的组分测定，我们提出非金属输运特征与热力学金属行为的共存可归因于窄带材料对化学无序的高度敏感性。因此，Mo4TGa16Ge的发现与研究为研究平带金属间化合物中无序控制的输运提供了一个化学可调平台。
英文摘要
Flat-band electronic states can be highly sensitive to chemical perturbations, offering opportunities to access a broader range of electronic behaviors beyond that of parent materials. Here, we report the discovery of a new series of compounds, Mo4TGa16Ge (T = Co, Rh, or Ir), derived from the strongly correlated flat-band superconductor, Mo4PtGa17, via nominally preserving the total valence electron counts. All three materials crystallize in a noncentrosymmetric cubic space group, F-43m, with Ge selectively occupying one of the Ga sites in the parent compound. Although the total electron count remains the same, Mo4TGa16Ge exhibits significantly distinct properties from Mo4PtGa17. Theoretical calculations predict metallic electronic structures with narrow, dominant Mo-d states at the Fermi energy, while low-temperature heat capacity results demonstrate finite Sommerfeld coefficients. However, electrical transport measurements show predominantly non-metallic behaviors with small observed activation energies, excluding the possibilities of conventional semiconducting behaviors. Combining chemical bonding analysis, electronic structure and compositional determination from X-ray crystallography and spectroscopy, we propose that the coexistence of the non-metallic transport features and the thermodynamically metallic behaviors can be attributed to the high sensitivity of the narrow-band materials to chemical disorders. Thus, the discovery and investigation of Mo4TGa16Ge provide a chemically tunable platform for studying disorder-controlled transport in flat-band intermetallics.
发表机构
- Department of Chemistry, University of Pittsburgh（匹兹堡大学化学系）
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