Hg2SiTe4 is found to be stable at room temperature and pressure and crystallizes in the I4̅ space group. The tetragonal compound (a = 6.04681(3) Å, c = 12.01208(9) Å, Z = 2) exhibits p-type electronic conduction and ultralow thermal conductivity (κtotal < 1 W/m K at 50 °C). The crystal structure is determined via charge flipping using TOPAS software to analyze X-ray diffraction data on powder samples. The compound is synthesized from elemental precursors and requires densification before annealing to form the ternary compound, unlike the similar compound Hg2GeTe4. Several synthetic procedures are tested to determine the best method to form the novel compound. Measured thermal and electronic property data are discussed along with first-principles defect calculations to inform future doping or optimization studies. Defect calculations suggest that SiHg2+, VHg2−, and HgSi2− native antisite defects may pin the Fermi level deep within the bandgap. Throughout, we compare the crystallographic and electronic properties of Hg2SiTe4 to those of the similar, previously discovered compound Hg2GeTe4.
Porter et al. (Mon,) studied this question.