Mercury Thiogermanate Glasses HgS-GeS₂: Vibrational, Macroscopic, and Electric Properties

Abstract

Glasses in the pseudo-binary system (HgS) x (GeS2)1–x were synthesized over the concentration range of 0.0 ≤ x ≤ 0.5. The fundamental glass properties (macroscopic, electric, and vibrational) were studied using differential scanning calorimetry (DSC), direct current (dc) electrical measurements, Raman spectroscopy supported by DFT modeling, and X-ray diffraction. Mercury species in thiogermanate glasses essentially form chain-like (HgS2/2) fragments substituting bridging sulfur between corner- and edge-sharing GeS4/2 tetrahedra. This structural evolution results in a significant monotonic decrease of the glass transition temperatures from 480 to 270 °C. The room-temperature dc conductivity changes non-monotonically with increasing HgS content x over a limited range of 4 × 10–15 to 7 × 10–13 S cm–1. The electronic transport in insulating HgS-GeS2 glasses occurs via extended electronic states. Tetrahedral HgS4/4 fragments also appear in the glass network with increasing x. Their exact population needs further advanced structural studies using diffraction techniques.

Deciphering Fast Ion Transport in Glasses: A Case Study of Sodium and Silver Vitreous Sulfides

“…Other information related to temperature regimes and synthesis details was reported elsewhere. 30,38 A Bruker D8 Advance diffractometer was used to verify the crystal structure of the synthesized references, which was found to be coherent with the reported results. 39−41 2.2.…”

Raman Spectroscopy and DFT Modelling of Tl2S-GeS2 Crystals and Glasses

“…All the structures were optimized using the tight convergence option ensuring adequate convergence and reliability of computed wavenumbers. Further details of the DFT simulations are published elsewhere [20] [32].…”

“…Heavy metal chalcogenide glasses appear to be promising optical materials transparent in far-IR [1][2], highly sensitive membranes for heavy metal ion detection [3][4][5][6] and interesting model materials exhibiting heavy ion transport in solids [7][8][9][10][11][12][13]. Structural studies of lead, cadmium, mercury or thallium chalcogenide glasses are rather rare, except for a few reports [14][15][16][17][18][19][20]. In the (Tl2S)x(GeS2)1-x system, glasses are formed over the entire composition region at x ≤ 0.5 [13].…”