Related Experiment Video
Updated: Jul 15, 2025
06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
7.2K
Pressure-Driven Structural and Electronic Transitions in a Two-Dimensional Janus WSSe Crystal.
Meiling Hong1, Lidong Dai1, Haiying Hu1
1Key Laboratory of High-Temperature and High-Pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guizhou 550081, China.
Inorganic Chemistry
|September 29, 2023
Summary
This study reveals how tungsten selenium telluride (WSSe) behaves under high pressure. WSSe undergoes phase transitions and becomes metallic, with unique behaviors under hydrostatic versus non-hydrostatic conditions.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Solid State Chemistry
Background:
- Janus transition-metal dichalcogenides (TMDs) are a class of materials with unique layered structures.
- Understanding the high-pressure behavior of WSSe is crucial for exploring its potential applications.
Purpose of the Study:
- To investigate the high-pressure structural stability and electrical transport properties of WSSe.
- To elucidate the effects of hydrostatic and non-hydrostatic conditions on WSSe's phase transitions and metallization.
Main Methods:
- Raman spectroscopy
- Electrical conductivity measurements
- High-resolution transmission electron microscopy (HRTEM)
- First-principles theoretical calculations
Main Results:
- Under non-hydrostatic conditions, WSSe exhibited a phase transition at 15.2 GPa and a semiconductor-to-metal crossover at 25.3 GPa.
- Hydrostatic conditions showed a ~2.0 GPa pressure hysteresis for phase transition and metallization due to feeble deviatoric stress.
- Bandgap closure was theoretically confirmed as the mechanism for metallization.
- Reversibility of the phase transition was observed upon depressurization via HRTEM.
Conclusions:
- This research provides the first report on the high-pressure behavior of WSSe.
- The findings enhance the understanding of crystalline structure and electronic properties in Janus TMDs.
- The study supports the development of novel functional devices based on WSSe.
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
26.7K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
26.7K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
42.8K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
42.8K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
1.6K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
1.6K
02:54Molecular and Ionic Solids
17.2K
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
17.2K
02:54Trends in Lattice Energy: Ion Size and Charge
24.0K
An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure of the strength of this attraction. The lattice energy (ΔHlattice) of an ionic compound is defined as the energy required to separate one mole of the solid into its component gaseous ions. For the ionic solid sodium chloride, the lattice energy is the enthalpy change of the process:
24.0K
02:22Structures of Solids
14.2K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
14.2K