A high pressure x-ray diffraction study of titanium disulfide

Abstract

A high pressure angle dispersive synchrotron x-ray diffraction study of titanium disulfide (TiS(2)) was carried out to pressures of 45.5 GPa in a diamond-anvil cell. We observed a phase transformation of TiS(2) beginning at about 20.7 GPa. The structure of the high pressure phase needs further identification. By fitting the pressure-volume data to the third-order Birch-Murnaghan equation of state, the bulk modulus, K(0T), was determined to be 45.9 ± 0.7 GPa with its pressure derivative, K'(0T), being 9.5 ± 0.3 at pressures lower than 17.8 GPa. It was found that the compression behavior of TiS(2) is anisotropic along the different axes. The compression ratio of the c-axis is about nine times larger than the a-axis when pressures are lower than 1 GPa. It suddenly decreases to three times larger at pressures of about 3 GPa. This ratio shows a linear decrease with a slope of negative 0.048 at pressures below phase transformation.

Creating new layered structures at high pressures: SiS2

“…It is isostructural to CdI 2 (C6 structure)43 where sheets are stacked directly above each other. The same structure is found at ambient pressure in chemically similar systems with heavier atoms such as SnS 2 44 or SiTe 2 45 as well as in several other chalcogenides, iodides, chlorides and bromides4346474849, or even in BeH 2 50. The second lowest-enthalpy phase P 6 3 mc contains two layers per unit cell which are mutually staggered and reflected with respect to each other - Fig.…”

Pressure controlled transition into a self-induced topological superconducting surface state

“…Using the data set reported in Ref. 41 for a / a 0 , c / c 0 , and z , we obtain another topological phase diagram, which is depicted in Fig. 2(b).…”

“…This means that our conclusions stay valid even when the discrepancy in the experimental lattice constant is 10 to 20 times larger than that of Refs. 37 and 41. One of the most important consequences of a topologically nontrivial state is the existence of a gapless surface state3942434445464748, which is protected by the combination of spin-orbit coupling and time-reversal symmetry and shows a spin-textured Dirac-like behavior1617181949.…”

Ultrahigh‐Pressure Phase Transitions in FeS2 and FeO2: Implications for Super‐Earths' Deep Interior

“…However, theoretical simulations predicted a Pa3 -P4 2 /n phase transition in NiS 2 at 150 GPa, in which the stable range of the Pa3 structure was much smaller than that of the Pa3-type FeS 2 (Yu & Ross, 2010). Furthermore, a pressure-induced phase transition in TiS 2 , another first transition metal disulfide, was observed at 20.7 GPa (Aksoy et al, 2008). Obviously, there exists significant discrepancy about the phase stability between the results from shock experiments and those conducted on similar first transition metal disulfides in the view of crystal chemistry.…”