Tl₁₀Hg₃Cl₁₆: Single crystal growth, electronic structure and piezoelectric properties

Single crystal of the ternary halide Tl₁₀Hg₃Cl₁₆ was grown using Bridgman-Stockbarger method. For the Tl₁₀Hg₃Cl₁₆ crystal, we have measured X-ray photoelectron spectra for both pristine and Ar⁺ ion-bombarded surfaces and additionally investigated photoinduced piezoelectricity. Our data indicate that the Tl₁₀Hg₃Cl₁₆ single crystal surface is very sensitive with respect to Ar⁺ ion-bombardment. In particular, Ar⁺ ion-bombardment with energy of 3.0 keV over 5 min at an ion current density of 14 μA/cm² causes significant changes of the elemental stoichiometry of the Tl₁₀Hg₃Cl₁₆ surface resulting in an abrupt decrease of the mercury content in the top surface layers of the studied single crystal. As a result of the treatment, the mercury content becomes nil in the top surface layers. In addition, the present XPS measurements allow for concluding about very low hygroscopicity of the Tl₁₀Hg₃Cl₁₆ single crystal surface. The property is extremely important for the crystal handling in optoelectronic or nano-electronic devices working at ambient conditions. The photoinduced piezoelectricity has been explored for Tl₁₀Hg₃Cl₁₆ depending on nitrogen (λ=371 nm) laser power density and temperature. - Graphical abstract: As-grown single crystal boule of Tl₁₀Hg₃Cl₁₆; dependence of the effective piezoelecric coefficient d₃₃ versus the photoinducing nitrogen laser power density, I, at different temperatures, T; and packing of the polyhedra of halide atoms around Hg atoms in the Tl₁₀Hg₃Cl₁₆ structure. - Highlights: • High-quality Tl₁₀Hg₃Cl₁₆ single crystal has been grown by Bridgman-Stockbarger method. • Electronic structure of Tl₁₀Hg₃Cl₁₆ is studied by the XPS method. • Tl₁₀Hg₃Cl₁₆ single crystal surface is sensitive with respect to Ar⁺ ion-bombardment. • Very low hygroscopicity is characteristic of the Tl₁₀Hg₃Cl₁₆ surface. • Photoinduced piezoelectricity is studied for the Tl₁₀Hg₃Cl₁₆ compound.