The structure of the orthorhombic room temperature and monoclinic low temperature form of Zn5Sb4In2−δ projected along the a direction. Cyan, red, and grey circles denote Zn, Sb, and In atoms, respectively. The Sb substructure corresponding to rows of face-sharing square antiprisms is shown by thin lines. Atom pairs Zn-Zn and Zn-In stuffing tetragonal channels are connected by thick lines.
Resistivity and thermopower (Seebeck coefficient) for different samples Zn5Sb4In2−δ (A, crystalline; B, cold pressed).
Specific heat C (open circles) as a function of temperature T of Zn5Sb4In2−δ together with the fitted phonon contribution (solid line) using a simple Debye-Einstein Model. The dashed line indicates the upper Dulong-Petit limit assuming δ = 0.15. Inset (a) shows the broad anomaly ΔC (open circles) by subtraction of the phonon contribution from experimental data. The solid line represents the integrated enthalpy of the phase transition. Inset (b) displays the change in entropy of the phase transition.
(a) Carrier concentration for different samples Zn5Sb4In2-δ (A, crystalline; B, cold pressed). (b) Reflectivity spectra for Zn5Sb4In2−δ (red line, sample A2) and Zn4Sb3 (black, broken line) at 250 K. The spectrum for Zn4Sb3 is according to Ref. 18. (c) Mobility for different samples Zn5Sb4In2-δ (A, crystalline; B, cold pressed).
DSC heating (red line) and cooling trace (blue line) of Zn5Sb4In2−δ.
Powder XRD pattern (Cu Kα) for annealed samples Zn5Sb4In2−δ at 673 K (a), 723 K (b), and 773 K (c). Bragg positions for Zn5Sb4In2−δ hcp-Zn, InSb and β-Zn4Sb3 are shown as black, red, green, and blue bars, respectively. Additionally, diamond and triangle symbols mark main reflections from the decomposition products.
Backscattering SEM images for a sample Zn5Sb4In2−δ annealed at 473 K for 24 h showing islands and threads of segregated Zn.
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