•Phosphorus-doped Bi2Te3 films were synthesized on a stainless-steel electrode by electrochemical deposition.•The thermal conductivity of the film is 0.47 W m−1 K−1, which is one-third of the value observed in the bulk material.•The doped P atoms occupy the interstitial positions in Bi2Te3.Phosphorus-doped Bi2Te3 films were synthesized on a stainless-steel electrode by electrochemical deposition. X-ray diffraction, scanning electron microscopy and transmission electron microscopy confirmed that the films are single-phased Bi2Te3 solid solutions with a rhombohedral structure. The as-prepared films exhibit n-type characteristics with the Hall coefficient −1.76E−2 m3 C−1 and the electrical conductivity 280 S cm−1. The thermal conductivity is 0.47 W m−1 K−1, which is as low as one-third of the value observed in the bulk material. The doped P atoms occupy the interstitial positions between the two adjacent Te(1) layers connected by Van der Waals interaction in Bi2Te3.

By means of first-principles calculations, we have investigated the effects of rare earth elements (REEs) on the structures and mechanical properties of magnesium. The lattice parameters, elastic constants, bulk moduli, shear moduli, Young’s moduli and anisotropic parameter of these solid solutions have been calculated and analyzed. The nearest-neighbor distance between Mg and the REEs is also analyzed to explore the correlation with the bulk moduli. The results show that the 4f-electrons and atomic radii play an important role in the strengthening process. The anomalies of the lattice parameters and mechanical properties at Eu and Yb are due to the half-filled and full-filled 4f-electron orbital states. Finally, the increase of directional bonding character near the alloying elements may account for the anisotropy and brittleness of these magnesium alloys.

The metastable β′ phase is often the most effective hardening precipitate in Mg-Gd based alloys. In this paper, the structural, elastic and electronic properties of the recently identified β′-Mg7Gd precipitate in Mg-Gd binary alloys were investigated using first-principles calculations based on density functional theory. The lattice mismatches between the coherent β′-Mg7Gd precipitate and α-Mg matrix are discussed and used to rationalize the experimentally observed morphology of the precipitate. The mechanical properties were investigated through analysis of the single-crystal elastic constants and the polycrystalline elastic moduli. It is found that β′-Mg7Gd is brittle in nature. Strong covalent bonding in β′-Mg7Gd, as inferred from its electronic structure, further explains its mechanical properties. Our theoretical results show good agreement with experimental measurements.

Rare earth elements doped thermoelectric materials Yb1−xMxAl3 (M = Ho, Er and Tm) demonstrated anomalously enhanced shear modulus [Zhou J et al, Intermetallics, 2010; 18:2394]. However, the origin of the shear modulus enhancement has not yet been understood. In this work, we shed light on this mechanism by systematically analyzing the band structure and charge density near the Fermi energy of Yb1−xTmxAl3 under various shear stresses on the basis of ab initio total energy calculations. We have showed that the valence band maximum (VBM) is very sensitive to shearing and plays an important role for the shear modulus enhancement. Since the valence electron structures of Ho, Er and Tm in Yb1−xMxAl3 (M = Ho, Er and Tm) alloys are very similar, the present results will provide a fundamental understanding on the electronic origin of shear properties in these rare earth intermetallics.Highlights► Based on DFT calculations, Yb1−xMxAl3 (M = Ho, Er and Tm) compounds have been investigated. ► The shear modulus c44 for the Yb1−xMxAl3 alloys reaches a maximum at x = 0.5. ► The VBM of Yb1−xTmxAl3 is very sensitive to shearing and plays a vital role for understanding the c44 behavior. ► The decomposed charge-density distribution of VBM was studied.

Nanostructured phosphorous-alloyed Bi2Te3 thick films have been prepared by electrochemical deposition. The average grain size of the films was calculated to be 14–26 nm based on Scherrer's equation. The effect of P on the Seebeck coefficient of the Bi2Te3 thick film was investigated. The results show that P-alloyed thick film has n-type conductivity with the Seebeck coefficient of −35 μV/K. The correlation between P site occupancy in the crystal and the Seebeck coefficient was discussed.