Related Experiment Video
Updated: Sep 10, 2025
12:02
Determination of Thermodynamic Properties of Alkaline Earth-liquid Metal Alloys Using the Electromotive Force Technique
Published on: November 3, 2017
13.3K
Pressure-Induced Phase Transitions and Electronic Structure Evolution of Ba4Au
Xinyu Wang1, Qun Wei1, Jing Luo1
1School of Physics, Xidian University, Xi'an 710071, China.
Materials (Basel, Switzerland)
|August 28, 2025
Summary
The study reveals Ba₄Au undergoes two first-order phase transitions under high pressure, transforming from I4/mmm to Cmmm at 0.4 GPa and then to I4/m at 5.7 GPa, with significant volume changes.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Computational Chemistry
Background:
- Previous research explored high-pressure phases of Ba-Au alloys (Au₂Ba, AuBa, Au₂Ba₃).
- The Ba₄Au compound's behavior under pressure remained largely uninvestigated.
Purpose of the Study:
- To investigate the high-pressure structural evolution and electronic properties of the Ba₄Au compound.
- To provide theoretical guidance for experimental exploration of Ba₄Au under compression.
Main Methods:
- Employed particle-swarm optimization for comprehensive structure searches at various pressures (0-50 GPa).
- Utilized first-principles calculations to determine structural stability and electronic properties.
- Performed enthalpy-difference calculations to identify phase transition points.
Main Results:
- Identified two first-order phase transitions in Ba₄Au: I4/mmm to Cmmm at ~0.4 GPa, and Cmmm to I4/m at ~5.7 GPa.
- Observed significant volume collapses associated with both phase transitions.
- Analyzed changes in electronic properties of Ba₄Au before and after phase transitions.
Conclusions:
- The high-pressure behavior of Ba₄Au is characterized by distinct structural transformations.
- Compression significantly alters the physical and chemical properties of Ba₄Au.
- Theoretical predictions offer critical insights for future experimental studies on this barium-gold compound.
Keywords:
crystal structure predictionfirst-principles calculationsgold-based alloysphase transitionsMore Related Videos
07:24Quantitative Atomic-Site Analysis of Functional Dopants/Point Defects in Crystalline Materials by Electron-Channeling-Enhanced Microanalysis
Published on: May 10, 2021
6.4K
09:06Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
Published on: March 24, 2019
8.2K
Related Concept Videos
03:02Colors and Magnetism
12.3K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.3K
02:42Valence Bond Theory
9.2K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
9.2K
02:58Crystal Field Theory - Octahedral Complexes
27.4K
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...
27.4K
02:31Phase Transitions
20.2K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
20.2K
02:46Electron Configurations
19.8K
Electron configurations and orbital diagrams can be determined by applying the Aufbau principle (each added electron occupies the subshell of lowest energy available), Pauli exclusion principle (no two electrons can have the same set of four quantum numbers), and Hund’s rule of maximum multiplicity (whenever possible, electrons retain unpaired spins in degenerate orbitals).
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p,...
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p,...
19.8K
01:19Phase Diagram
6.1K
The phase of a given substance depends on the pressure and temperature. Thus, plots of pressure versus temperature showing the phase in each region provide considerable insights into the thermal properties of substances. Such plots are known as phase diagrams. For instance, in the phase diagram for water (Figure 1), the solid curve boundaries between the phases indicate phase transitions (i.e., temperatures and pressures at which the phases coexist).
6.1K