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A variable temperature single crystal X‐ray diffraction study of the ternary compound, Cu4TiTe4 is reported between 200–400 K. The temperature dependent study indicates the compound undergoes an order‐disorder phase transition at ∼320 K. Below the transition temperature, the phase that crystallizes in the primitive cubic space group P4‾ ${\bar{4}}$ 3 m with lattice parameter of a≈5.9 Å, transforms into the two‐fold superstructure. It is modeled as a fourfold twinned rhombohedral structure. The transition is reversible. To relate the phases, a group‐subgroup symmetry relations are established. Upon decreasing temperature, the atomic ordering is noticed in the occupationally disordered Cu‐sites of Cu4TiTe4. This characteristic structural rearrangement may have a significant impact on the electronic structure of Cu4TiTe4. Hence, the detailed structural characterization is supposed to be useful for further understanding of thermoelectric transport properties in the Cu4TiTe4. [ABSTRACT FROM AUTHOR]

A variable temperature single crystal X‐ray diffraction study of the ternary compound, Cu4TiTe4 is reported between 200–400 K. The temperature dependent study indicates the compound undergoes an order‐disorder phase transition at ∼320 K. Below the transition temperature, the phase that crystallizes in the primitive cubic space group P4‾ ${\bar{4}}$ 3 m with lattice parameter of a≈5.9 Å, transforms into the two‐fold superstructure. It is modeled as a fourfold twinned rhombohedral structure. The transition is reversible. To relate the phases, a group‐subgroup symmetry relations are established. Upon decreasing temperature, the atomic ordering is noticed in the occupationally disordered Cu‐sites of Cu4TiTe4. This characteristic structural rearrangement may have a significant impact on the electronic structure of Cu4TiTe4. Hence, the detailed structural characterization is supposed to be useful for further understanding of thermoelectric transport properties in the Cu4TiTe4. [ABSTRACT FROM AUTHOR]

The newly synthesized ultralow thermal conducting Cu4TiSe4 undergoes a temperature‐induced reversible structural phase transition at −92 °C. The room temperature structure exhibits cubic symmetry (space group P4‾ 3 m with lattice parameter a=5.6458(1) Å) and shows positional disorder in two Cu‐sites (4e and 1a Wyckoff sites). In this report, a structural study was carried out on the same sample by means of single‐crystal X‐ray diffraction data (nitrogen‐cryostat) collected at 131 K. At this temperature, Cu4TiSe4 crystallizes in rhombohedral symmetry, space group R3 m, with a=7.9538(5) Å and c=19.4828(17) Å. The low temperature structure is fourfold twinned. In the low temperature phase, copper atoms at 9b and 3a Wyckoff sites (originally 4e and 1a Wyckoff sites in the room temperature structure) order partially in comparison to room temperature structure. This temperature induced phase transition induce slight increase of the thermal conductivity of the material. [ABSTRACT FROM AUTHOR]

The newly synthesized ultralow thermal conducting Cu4TiSe4 undergoes a temperature‐induced reversible structural phase transition at −92 °C. The room temperature structure exhibits cubic symmetry (space group P4‾ 3 m with lattice parameter a=5.6458(1) Å) and shows positional disorder in two Cu‐sites (4e and 1a Wyckoff sites). In this report, a structural study was carried out on the same sample by means of single‐crystal X‐ray diffraction data (nitrogen‐cryostat) collected at 131 K. At this temperature, Cu4TiSe4 crystallizes in rhombohedral symmetry, space group R3 m, with a=7.9538(5) Å and c=19.4828(17) Å. The low temperature structure is fourfold twinned. In the low temperature phase, copper atoms at 9b and 3a Wyckoff sites (originally 4e and 1a Wyckoff sites in the room temperature structure) order partially in comparison to room temperature structure. This temperature induced phase transition induce slight increase of the thermal conductivity of the material. [ABSTRACT FROM AUTHOR]