Structural stability of WS₂ under high pressure

Abstract

Structural behavior of bulk WS 2 under high pressure was investigated using synchrotron X-ray diffraction and diamond anvil cell up to 52 GPa along with high temperature X-ray diffraction and high pressure Raman spectroscopy analysis. The high pressure results obtained from X-ray diffraction and Raman analysis did not show any pressure induced structural phase transformations up to 52 GPa. The high temperature results show that the WS 2 crystal structure is stable upon heating up to 600 • C. Furthermore, the powder X-ray diffraction obtained on shock subjected WS 2 to high pressures up to 10 GPa also did not reveal any structural changes. Our results suggest that even though WS 2 is less compressible than the isostructural MoS 2 , its crystal structure is stable under static and dynamic compressions up to the experimental limit.

Pressure induced metallization with absence of structural transition in layered molybdenum diselenide

“…More importantly, size effect of different transition metal cations is also expected to change the interlayer interactions. Previous studies on WS 2 and WSe 2 46 47 48 showed that they experience continuous lattice contractions under pressure. W 2+ has broader electron orbitals and may introduce stronger interlayer interactions than Mo 2+ , which results in the absence of layer sliding in WS 2 .…”

“…Previous studies have reported many electronic transitions such as insulator to metal or semiconductor to metal transitions in the group of binary chalcogenides, see for example, Bi 2 X 3 31 49 50 , Sb 2 X 3 51 52 53 , and Ag 2 X 54 55 56 . For structures starting with vdW gaps at ambient conditions, the closure of their vdW gaps is generally accompanied or followed by first-order structural transitions where large structural re-constructions or atomic movements take place 43 44 45 46 47 48 . However, in the case of MoSe 2 , the metallization process does not involve any sudden change in the crystal structure, which allows its electronic structure to be continuously tuned.…”

Pressure-Modulated Conductivity, Carrier Density, and Mobility of Multilayered Tungsten Disulfide

“…Selected pressure and temperature Raman profiles show phonon hardening as well as the E 2g mode being suppressed at high pressures (Figure 4b), which has also been observed in other TMDs. 6,38 Suppression of the intensity ratio between the A 1g and E 2g modes decreases with pressure (Figure S5a), and the suppressed E 2g mode is associated with broadening of the FWHM at higher pressures ( Figure S5b). At higher temperatures, the 2LA(M) mode is more prominent (Figure 4b) and the FWHM is observed to increase with temperature for all Raman modes (Figure S5c).…”

2D Materials and Heterostructures at Extreme Pressure

“…phonon hardening effects are ascribed to the anisotropic compression in the different directions (i.e., the out-of-plane and inplane directions) and enhanced interlayer interactions induced by the increasing pressure. [17][18][19][20]159] Monolayer WS 2 under high pressure (up to around 25 GPa) and on different substrates including Si/SiO 2 and DAC surfaces has been investigated. [160] According to the occurrence of Raman-inactive B modes, differentdegree structural distortions have been observed.…”